Being sued by credit card collections

I had 20 days from the time of being served to respond whether I agree or disagree to the debt of the small claims notice. I have a very short time left to respond due to having to wait to hear back from legal aid with materials I could use as a defense, etc. I'm being sued for $513 dollars plus court costs. Although I am not positive I agree with owing 513 and am unsure of where that amount has come from, I DO acknlowedge there is a legitimate debt. I am still unsure of what to do. In my state I can fill out an exempt form for wage garnishment because I only work part time and do not make enough for them to garnish anything. I am not sure if that means they can still garnish my bank account though..which is where my paycheck gets direct deposited. Also, legal aid has really not been a whole lot of help because they're a free service. It takes hem forever to get back to me and answer my questions. I have tried calling and emailing the plaintiff to see if this can be retracted and I can make a payment plan with them but have not heard back and like I said I'm cutting it short on time. I'm getting worried/anxious. Anyone have advice on what YOU would PERSONALLY do in this situation? Or anyone been in a similar scenario? Please no rude or negative comments. I am FULLY aware of my mistakes and do not need judged for them. I have learned lessons from this and want to make it right, just not sure how. Thanks in advance!