Refusal to cancel or swop faulty, contract fone since January 2019

Good day, I am in need of guidance please.

I took a cell contract with CellC in January 2019, within 7 days I called them to tell them the fone is faulty. I booked the fone in the next day.

Since then I had the fone back, each time for less than a week, booked it in for repairs X5, from January to April 2019.

The last time I booked it in, I requested Cell C terminate my contract or swop my contract for a different make device. I'm paying for a contract fone that I don't have in my possession.

They've informed me this morning that they're not doing either, the faulty fone is back at the shop for collection from me. Can you please advise what I can do? Thanks & Many blessings.