Samsung A30S

@MTN and @Samsung my patience with you has run out !! I got a contract phone from MTN, less than a year into the contract the phone just went blank and I took it back .The phone took 40 days to be repaired and returned to me .Less than a month after I received the phone from repairs ,it stopped charging. Took it in again for repairs not knowing that would be the last time I see my phone .Someone from Samsung called me and said my phone is back from repairs so I went to pick it up from MTN and the lady from MTN told me they never received the phone . After numerous emails between Samsung and MTN noone has an answer on the whereabouts of my phone and yet i still have to pay for it . What further steps can I take against these two companies .