Incredibly Frustrating

Have been trying to obtain a paid up letter for the past 5 months. Only response I keep getting is that they either cannot find an account linked to my name or they say it will be escalated. 5 months later no response. They say account had been handed over to Norton Lambrianos Attorneys, both firms are though escalating with no response and ignoring me. Sent through statements they sent me and still no response. Any advise, has anyone managed to come right?????