Dropped Calls

I've been trying to get a Prescribed / Paid Up letter from Sheet Street since November. When I call I have to wait for someone to answer and then my call gets dropped. I'm wasting hundreds of rands in airtime with the calls. Today again after 2 dropped calls and waiting for nearly 18 minutes on the phone I was told they do not have my id number on their records and I will be transferred to the Admin department to see whether they can assist, and again my call is disconnected. All I want is a prescribed / paid up letter from Sheet Street, according to TransUnion & Experian I still have an account with you so how can you not have my id number on record? This is very disappointing service.