VERY UNHAPPY and FED-UP with bad service

I upgraded to BB9720 in March '15. From the start I had problems, but could tolerte it. After a month it gradually got worse, with phone switching off randomly. Then Whatsapp stared giving problems, not being able to save/open photo's or videos sent. Even after I removed whatsapp, and re-installed it, problem persisted. I then got a bigger mg memory card, to no avail! Last week my phone did not want to read my memory card anymore, and the camera stopped working! Takes pics, but not saving it! Sent it in 13 aug for repairs, miraculously done by 14th, replacing battery and downloading software. Got it last night, put on charge. This morning, catching up on all missed calls/messages etc. The phone switches off randomly!!! On again...checked camera - not working!!! Check memory card - not reading it!!! So if it is fixed, what did they do??? All problems still there!!! Not even going to start on problem with airtime beginning of august, and the telephone conversations around that, till 14th!!!! N. O. T. Happy at all!!!