How do you respond to an appeal filed after a district court default judgement?

This is a background of the situation....I am a contractor. Several months ago I had customers sign a contract to have work done in their home. The contract outline what was going to be done and allowance amounts (Flooring, Plumbing, Electrical etc.) The customers went over and under on several things. They made all payments except the final bill after the work was completed. The final bill consisted of the last percentage of the total job unpaid. Minus allowances, and returned unused material and extras that resulted from changes made by the homeowners through the construction process. The homeowner’s claimed they ran out of money, and now that the job was complete they could refinance. I was told that when they got their money I would be paid. However, 60+ days and several unreturned phone calls went by and I was forced to file a civil complaint with district court for roughly $3500.00 (balance, late fees, and court costs). They failed to attend the hearing and a default judgement for the sum was reached on my behalf. While leaving the district court that day the customers actually called my cell phone and said they were not attending...and there was a check taped to their front door. I was instructed by the district court not to close the case until we were sure that the check was for the correct amount and that it actually cleared the bank. The check was for $3100.00. Missing the late fees and court costs. Shortly after they received the default judgement total, and have filed an appeal. We received a copy of the paper they filled out requesting the appeal. It does not instruct us as to who or what we need to do to proceed for the additional money. It also does not inform us as to what they are actually appealing (the last $400.00, the whole last payment, or the total job?) The District court told us they are no longer involved. The county court told us they can not offer any legal advise, not even how to proceed. I don’t know at this point if it is small claims court, and or if I need to hire an attorney to represent my behalf. Any advise?

Is the paper a form used by the court or their own filing/

It is a pink carbon copy of what they used to file their appeal...I have since received another letter, a Notice of Judge Assignment-Arbitration. But it doesn't say anything other then the case has been assigned to the Arbitration Track for caseflow management, and the name of the Judge.