There is no obvious answer to this question because it depends on a specific timeline of facts, the terms of the original agreement, the terms of the judgment the creditor has against you, and / or the statutory interest rate. You should call a local consumer law attorney for more help with your question.
My answer is for only informational purposes and is not legal advice. I am licensed to practice law in Oregon and I recommend contacting a local attorney for the best help with your legal questions.
I agree that there are many other facts that need to be established before answering your question. There are statutes regarding "bad checks" and there are separate statutes allowing post-judgment interest on debts. You should have been served with a copy of the summons and complaint before the plaintiff was able to get a judgment, thus giving you a certain time period to respond with a formal answer/defense. I also agree that you may need to speak to a consumer rights attorney to assess the validity of the garnishment/judgment/underlying debt.
This info is for basic information only and no attorney-client relationship should be construed. If you need actual legal representation, you should consult with a lawyer in your area who is licensed to practice in your state.
I believe you should contact a local attorney as soon as possible, and prove that attorney with more facts, hope you find success in that.
Please do not take my answer to be legal advice that would establish any attorney-client relationship. Please take it as a general response from my own experience in response to your question. I hope you find it helpful.