My iPhone repair for over 2 months and 3 more weeks to go

So my iPhone 7 plus was freezing and extremely slow until I decided to take it back to mtn(because it is on contract). So they took it in beginning of july and told me that it will take 7 to 14 working days to fix..It is the 11th of September today and i still don't have my phone..Every time I call them or their repairs centre I am given a different story..MTN new market mall customer service is also very bad.