Service Centre no answer

Early April i logged a request for my oven . 2 days later a guy came out to me and had a look and i paid him the call out fee cash as i was told by the call centre . i signed and he told me f i still have issues in the next 6 months i can just call again as this same callout is valid for 6 months if its the same issue, and he said the office will send a receipt ...Of course no receipt received . i call *** and the rudest gentleman is on the line , and says i should call *** for the receipt. Here no one answers or they pick up and drop the call immediately . For such a simple query i had to call 3 times , spend over 10 mins hanging on the line , with still no answer .