HOW MANY TIMES MUST I SEND MY PHONE TO OBF!!!

my 2nd contract purchased on 18/04/15, And from this time I've been only able to use the phone for 5 days!My handset has been in for 3 OBF's & the previous 2 had not been granted because ur technicians couldn't replicate the issue- the double tap feature,network signal continuously dropped,dropped calls,& some apps weren't working,however I did set aside these issues after the 2nd OBF was turned down.I got my phone back last Tuesday(May 5),and used the phone for a few days. My signal had completely dropped to EDGE and couldn't receive 3G,HSDPA. I made 2 complaints on the same fault and nothing was replaced,I'm unsatisfied with Cellc's service, especially since it's a new handset that I went to return the very next day after purchase.I don't want a refund.I want to choose another device and I'm more than willing to pay the difference. Why do I have to pay for a phone that doesn't work!I have now received a reply from Cellc Repairs stating that it was rejected due to not being able to replicate and they stated that it was stuck on EDGE because Mobile Data was turned Off. However a video was taken in the store by a consultant showing settings were all right. This contradicts them