Maximum Interest on Default Judgements

There's a default judgement against me since 2005. I wasn't aware of it since I was served improperly. Now comes a new junk debt buyer in 2011 who bought the 2005 debt and decided to file for writ of garnishment. The court granted it and now my bank account is frozen. The original debt is 2,000, but now is 11,000 with 18% interest, court costs, lawyer's fees, etc. I came across your website that the maximum they can charge on interest is 10% in Texas when there is a judgment. Does this still remain true? Also, where can I find that stated in Texas Law? I want to forward it on to the creditor's lawyer in hoping they will have to drop the interest rate.