Legal Question in Bankruptcy in Pennsylvania

You can't. If the debtor is seeking to discharge this debt in bankruptcy, then the debt will be discharged. If the debtor voluntarily wants to repay you or voluntarily reaffirms the debt (this has to be done in bankruptcy with the approval of the bankruptcy court) then you cannot force the debtor to repay you. The only exception would be if this debt is not of the kind that would be dischargeable in bankruptcy (like some tax debt, student loan debt, child support or fines are not dischargeable) then you can resume trying to collect on the debt once the debtor is out of bankruptcy. If the debtor filed a chapter 7, most of those are "no asset" cases meaning that there are no assets to be distributed to the creditors. You would not file a proof of claim in such case as there is nothing to get. The debt is simply wiped out.

You are welcome to get a second opinion and should speak with a bankruptcy attorney who specializes in representing creditors as I don't practice bankruptcy. However, as I represent debtors I do hae to know something about it, hence my advice to you.