What country/state are you from, what country state is your client from and how much money are we talking about? In the US there is a fairly straightforward process to sue someone in small claims court without a lawyer and with fairly small fees. But small claims courts are limited to small awards.
I have not worked as a freelance programmer nor hired any, but a friend really likes to hire freelancers for various projects and often asks me for advice and tells me about his travails. I think practically speaking, it is not that hard for a freelancer to get paid because software always needs upkeep for bugfixes or updates to work with other software or to add new features. And it is far far far more expensive to have a second freelancer look at the first freelancers code and do the updates.
Some people say it takes more time to read code than to write it. I am not sure if that is true but very often if you ask a second freelancer to do minor updates on another freelancers code, the second guy will just say that the code is so awful the whole thing has to be rewritten from scratch. So you have a big advantage just by having written the stuff and having the code in your head and written in your style. You are the best man to fix it and update it by far.
My friend always pays his bills but he is a very tough negotiator, and often gets comparatively good bargains for freelance work. However, all the benefits of his bargains disappear when he needs the software to be changed a bit in six months or so. Then the freelancer is in the drivers seat and my friend completely drops his tough negotiator stance and becomes super nice and friendly towards the freelancer.
So if you do not want to pay for lawyers and small claims court is not suitable for some reason, you may just send a demand letter saying that you are charging a 20% penalty for non-payment and interest will accrue in the future, and just wait for your client to need some update and then you demand that all previous invoices be satisfied before discussion for new work even begins.
IANAL, this is not legal advice. If the sum is a large amount, it would probably be best to consult a lawyer.
I have not worked as a freelance programmer nor hired any, but a friend really likes to hire freelancers for various projects and often asks me for advice and tells me about his travails. I think practically speaking, it is not that hard for a freelancer to get paid because software always needs upkeep for bugfixes or updates to work with other software or to add new features. And it is far far far more expensive to have a second freelancer look at the first freelancers code and do the updates.
Some people say it takes more time to read code than to write it. I am not sure if that is true but very often if you ask a second freelancer to do minor updates on another freelancers code, the second guy will just say that the code is so awful the whole thing has to be rewritten from scratch. So you have a big advantage just by having written the stuff and having the code in your head and written in your style. You are the best man to fix it and update it by far.
My friend always pays his bills but he is a very tough negotiator, and often gets comparatively good bargains for freelance work. However, all the benefits of his bargains disappear when he needs the software to be changed a bit in six months or so. Then the freelancer is in the drivers seat and my friend completely drops his tough negotiator stance and becomes super nice and friendly towards the freelancer.
So if you do not want to pay for lawyers and small claims court is not suitable for some reason, you may just send a demand letter saying that you are charging a 20% penalty for non-payment and interest will accrue in the future, and just wait for your client to need some update and then you demand that all previous invoices be satisfied before discussion for new work even begins.
IANAL, this is not legal advice. If the sum is a large amount, it would probably be best to consult a lawyer.