It seems like I bought a dummy phone

On the 17th of March 2020 I bought a cellphone Nokia 3.2 costing R2599 at truworths in Queenstown cartcath road, on the 1st of June 2020,I returned the phone to truworths due to the fact that it had speaker problems, it was sent to mnt for repairs, 26th June 2020 I received a call from truworths telling me to come and collect my phone it has been fixed,however upon checking the phone I found out that it had been further damaged, from speaker problems to the phone having a blank screen,which makes it impossible for me to use the phone in any way, 29th of June 2020 I returned the phone again to the store and I told the person incharge of the store that I no longer want the phone they should refund me or replace the phone with a new phone as I am still paying for a phone that I am currently not using, however she insisted on taking back the phone to MTN for warranty assessment,now am without a phone, a phone that am expected to pay for each month, the store has been sending me from piller to post,I also spoke to the area manager of the store who was very rude towards me, the treatment I have been getting regarding this matter is totally unacceptable, it seems like I bought a dummy phone, complaint by Thami Tyembile.