Spiralling costs and poor quality legal services are adding to the misery of divorce, the law watchdog has said.
A report by the Legal Ombudsman for England and Wales showed complaints by clients in divorce and family law were higher than in any other category.
The Legal Ombudsman's role is to resolve disputes between lawyers and their clients.
The Law Society said it hoped the study would help to remind solicitors to provide clear information about costs.
Some 13% of clients were dissatisfied with their lawyers in divorce cases, almost double the level in other areas of the law.
About a quarter of those complaints related to cost, and one in five people said they were not given a cost estimate at the outset.
In one case a woman was charged £15,000 more than had been agreed at the outset, including £4,000 for photocopying, despite asking for proceedings to be stopped.
She took her case to the Legal Ombudsman which ordered the firm to waive the final bill.
"I did not know where to turn to - it was absolutely horrendous because I had no means at all of paying that bill," said Samantha Feely.
"And it was literally as a last resort... I went to the ombudsman. And ultimately the ombudsman has ruled in my favour that the bill should be wiped off - I didn't have to pay it. But it was a 12-month process."
She added: "I feel really bitter about it - I trusted the legal representation who were working for me."
She went on: "It doesn't matter whether you've been overcharged by £50, £500 or £15,000.
"There's a service there to be used, lawyers should be a bit more conscious and considerate to the situation that people are in - they are very vulnerable when they are going through this. It's not an easy time emotionally and the last thing you want is to be taken for a ride by lawyers that just think they have got a licence to print money."
In some cases bills exceeded what people were expecting by more than £30,000.
Apart from cost, 18% of divorce complaints involved a failure to provide an adequate service. This was often in the form of poor information.
In April, cuts to legal aid will result in 200,000 cases a year of divorce and family breakdown being removed from public funding, meaning more people will be paying privately.
The Legal Ombudsman recognised this and called on lawyers to improve the experience for clients.
Chief Legal Ombudsman Adam Sampson said: "Clearly lawyers could be doing more to reduce complaints by providing accurate cost information, providing decent service levels and by taking complaints seriously.
"I think this report challenges lawyers to raise their game and make the divorce process less painful for consumers."
Acrimonious divorces were exploited by some unscrupulous lawyers to maximise their earnings, Mr Sampson said.
"The best of the lawyers prioritise the needs of the individual, other lawyers however prioritise trying to get as much money as possible out of the individual client," he said.
"That can mean in something like a divorce, if you've got a very highly-charged vulnerable client sitting in front of you who's angry at their ex, then you don't actually choke off what the client wants which is to punish them through the courts, but you encourage them and the result is a massive bill."
BBC legal affairs correspondent Clive Coleman said the report would make uncomfortable reading for lawyers.
The Law Society, which represents solicitors in England and Wales, said lawyers had a professional obligation to provide clients with clear information about charges, and the report would be very helpful to lawyers and clients in reminding them of this.