Phone under warrantee damaged during repairs and returned 4 months later non-functional

My blackview S8 had a charging and software issue in Nov 2020, at under a year old. I sent it to blackview for repairs, under warrantee . At the same time, I asked them to replace my screen, which had a minor crack, at my cost. The phone came back after three weeks and over December, the screen started to malfunction - dead spots which made the phone non functional. The phone went back to blackview for repairs. Three weeks later, it came back and this time, it had an issue with the sim cards. When I placed both sim cards in my phone, if I set sim 1 as the data sim, sim 2 lost signal. Both sim cards work (and are still working simultaneously in a cheap hisense phone). Back to blackview it went. Two weeks later, it came back. This time, the battery is now a problem - it discharges to 85% and the phone crashes completely. Blackview have now acknowledged that they can do no further repairs so they are offering me a discount of R950 on a new blackview. This is less than the original value of the phone, which went in under warrantee, less than their cheapest phone and definitely less than the value of the cheapest phone with the same specs. To say that I am furious is an under statement - I sent them a phone under warrantee and four months later, I am still without a functional phone.