I'm sorry you lost your money but that's really bad advice. The proper solution was given below: send a letter (real, snailmail) demanding payment within 14 days or the debt will be passed to a debt collection agency.
If there's no response just do that. If you have a good paper trail you can get half your money from them and then forget about it. Plus you have the happy knowledge that the collection agency don't take no for an answer and will literally turn up at their office with a warrant and start taking equipment out to cover the debt.
Edit: I just noticed you said you didn't have a good paper trail. Well, an expensive lesson but I'm sure it's one well learned! :)
If there's no response just do that. If you have a good paper trail you can get half your money from them and then forget about it. Plus you have the happy knowledge that the collection agency don't take no for an answer and will literally turn up at their office with a warrant and start taking equipment out to cover the debt.
Edit: I just noticed you said you didn't have a good paper trail. Well, an expensive lesson but I'm sure it's one well learned! :)