Poor Communication and Service

On the 4th of Jan 16, we logged a windscreen claim with Boksburg PG glass, we were told that the windscreen for a Mercedes Benz Sprinter is out of stock and if we can come back on Friday the 8th the suppliers would have delivered it by then. On Friday I sent the driver to this branch to have the windscreen replaced but he was told that the windscreen is still out of stock. Saturday the 9th I decided to drive to the branch to get a clear indication on progress and to get a printout of the claim so that the driver can produce it as proof that we have logged a claim to traffic officials whenever he is stopped. The lady who assisted me with the printout then gave me the direct person who is working on my claim Thelma ***. On the following Monday the 11th I tried to call Thelma but the phone rang unattended. I tried again on Tuesday, Wednesday and Thursday with no luck. On Friday the 15th I decided to call the branch number *** and waited for more than 20 minutes before someone could pick up. I explained my story and dissatisfaction, the person on the phone told me they were still waiting for the supplier. How long am I supposed to wait for help at this branch? I'm lost.