Received a letter Back in XXXX. I responded and Asked for proof of debit Via fax ( i have proof of fax enclosed ). I also mailed out a copy that I faxed to them for proof of debit ( I have provided the printed tracking numbers as proof as well ) I got a letter today stating they are going to Sue us if we do not pay. This is the only response we have received and still have not been provided with any signatures and proof we owe this debt, or anything we have asked for in the letters we have sent.