Debt charities have warned families could "face real hardship" over delays in agreeing coronavirus-related car finance payment holidays.
Last week, the industry regulator instructed lenders to offer payment holidays to customers who need them.
But BBC Radio 5 Live has found that customers of some car finance providers still haven't been granted breaks, despite asking for the last six weeks.
However the industry body for lenders say they are doing everything they can.
In 2019, consumers borrowed £38bn to finance cars.
Tamara Ellison, from Suffolk, had only just started a new job at a graphic design agency when the company placed her on furlough in March.
But because the 48-year-old had only just started with the firm, she wasn't eligible for the government's Job Retention Scheme, which covers 80% of people's wages up to a cap of £2,500.
Tamara, whose income also supports her husband and 13-year-old son, has spent the last six weeks trying to agree a pay holiday with Volkswagen Financial Services (VFS), on her Volkswagen T-Roc, without success. She pays £302 a month in car payments.
Earlier this week, she told the BBC: "The car finance is my biggest outgoing and if they take another month's payment, the sacrifice will have to be food and utilities. I have got payment holidays on some utilities, but not all of them.
"It's so frustrating because I flagged this to them on 19 March - it's not for the want of trying."
After the BBC contacted VFS this week, Tamara's payment holiday was approved, but she says the process has been a "nightmare".
'I can ill afford the next payment'
David Needham, 63, a salesman from West Sussex, had just signed a finance deal for a new Audi A6 on 2 March that costs £635 per month.
But just 11 days later, the grandfather-of-two was furloughed. He has also been trying to secure a payment holiday with VFS since 19 March, with no success.
"When you factor in the insurance around one third of my furlough income is now going on my car and I've still got bills to pay," Mr Needham told the BBC.
"I travel a lot for work and have an allowance for my car. An awful lot of salespeople will be in the same position as me - they'll have got a new car at the start of the financial year which they can no longer afford.
"I can ill afford to make the next payment, but if I don't, I will fall into arrears and I'm worried that will mean I then don't qualify for the payment holiday."
On Friday 24 April, the Financial Conduct Authority (FCA) - the City regulator - finalised its package of measures, which set out how motor finance customers should be supported through the lockdown.
It said lenders should provide a three month payment freeze to people who are experiencing temporary difficulties meeting finance payments.
Many lenders, however, didn't wait for the guidance to be issued before starting to offer payment holidays.
According to the Finance and Leasing Association (FLA), in the six weeks to 17 April, lenders received around 425,000 forbearance requests and granted 312,000 - including payment holidays, payment reductions, waived interest or extending the term of an agreement.
However, VFS said it only started offering payment holidays on Monday 27 April, after the regulator's guidance was finalised.
But it says it did already have other support measures in place which customers could access.
VFS said it offers a range of options for customers in financial difficulty, the most recent being the option to apply for a three-month payment deferral.
It said it had seen "significant requests for this option", but for some people a payment deferral wouldn't be the right outcome, in which case the firm offers "a range of options and we work with the customer to find the best solution".
VFS' spokesman added: "Since the start of the lockdown, we have prioritised the needs of our customers at the same time as adjusting the way we work, in order to keep our colleagues safe and well.
"This means that we are doing things a bit differently and we may take longer than normal getting back to customers. The best way to get in touch is by using our online services and we would recommend contact by phone only if online is not available."
Peter Tutton, head of policy at debt support charity StepChange said: "While the FCA has taken welcome and unprecedented action to help those affected by the current crisis, it's clear there are still people in danger of experiencing real hardship, as a result of problems with their car financing contracts.
"We would urge firms to do all they can to anticipate this and to treat their clients as fairly as possible in the coming months."
He added that lenders could stop people from falling into problem debt by holding off "treating non-payments as defaults and by offering appropriate forbearance to those who need it".
Stuart Carmichael, chief executive of the Debt Support Trust, says a delay in agreeing payment holidays would be a huge concern for any driver during this time of "unprecedented financial uncertainty".
But he warned it would be a particular concern for customers who already had pre-existing arrears, because the new guidelines say lenders do not have to offer them a coronavirus payment holiday.
Instead, customers who have already missed payments may have to rely on existing provision for people who get into financial difficulty.
"It is these people we worry about most," he told the BBC.
"You could have lost your job and missed a couple of payments historically, but have got back on track with a new job and an agreed plan to make up the arrears - and now you've been furloughed and you're stuck. It doesn't seem fair."
A spokeswoman for the FLA said that where requests had not yet been dealt with, it might be because the lender was waiting for a response from the customer, or the customer could be waiting in a queue, due to the high volumes of requests.
She added: "If a customer is nearing a payment date and still has not heard from their lender, then please get in touch with them again."