Endless problems with cellphone after repairs done

I took my phone in for a charge pin repair and after untold problems it was fixed. Later in the year the LCD cracked and i took it in again to it replaced and it never was the same. I cannot believe the unprofessional manner in which matters are handled at VIP. I was accused of breaking my phone and Being ungrateful. As well as being told the world does not revolve around me. i was told i will be sued for defamation if I tell the truth of what happened. I was asked to provide an affidavit stating that the phone broke in their care for insurance purposes which i did and was later told that the claim was cancelled because the phone was fixed. When i asked for proof no one can reply to confirm the cancellation. I have a detailed letter highlighting all the problems as it happened. Today my phone was returned to me by one of their contractors who was never given permission to pick up my phone . How can they allow anyone to just return peoples phones without the work slips issued by VIP. Management never returns a call. Please can you advise me further i really am at my wits end. I did not have a phone for most of the year. Lost out on data as well as revenue. Many thanks.