Sterns Vangate Mall worse service ever.

need assistance with Sterns Vangate Mall. I purchased a mobile device at Sterns Vangate mall on the 12 November 2022, phone was working well until 28 January 2023, I put the device on charge 29th January I charged the phone whole day phone went up until 33%, left the phone on charge for the next day and still the same, left it for another day and the percentage was decreasing, eventually on the 3rd February I took the device to Sterns for them to please send away for repair. The device was sent away for assessment, repair was declined after 3 weeks and phone was sent back to store on the 22nd February. I went to collect phone, consultant assisted me to check phone, put on charge only to see the phone returned with same percentage it left 31% and she put the phone on charge to see if it was charging, I left the store to do what I needed to do, I returned about 1hr30 mins later and the percentage was even decreasing more, same day we sent the repair back to MTN, the phone was only collected from the store on the 17th March, its been 4 weeks for them to collect it from the store, they then returned phone to store on the 25th March advising part has been fixed however they not advising which part, I collected the phone from store on the 27th March, phone was 100%, phone then died and I put it again on charge the 28th March, only to find that the same problem, phone was on charge whole night and when I woke up the morning on 29th the phone was yet again only on 31%. I have advised I want a credit to my account or refund or even a new device as this is ridiculous to have a new device that has been sent away for repairs 3 times and the same problem still exists, this isn't fair on me that paid for a device, and it cannot be used. the phone was sent away 6 times and the phone still doin the same thing, logged a complaint with Ombudsman for MTN but that was resolved as MTN was not the problem, Sterns is as they should have refunded/given me a new device after the 3rd time phone was sent for repairs. i logged a complaint with the Ombudsman for Sterns yesterday and awaiting feedback, this is disgusting service received from them and i wont ever support them again