MTN bad after service!!!!

Bad after service. Renewed contract got new Samsung S20 FE on 2 June 2021. The phone keeps on dying. Took to MTN Middelburg Midwater Sentrum today 29 June 2021. No problem will send phone away will take between 7 days to a month. I don't have a problem give me a replacement phone please sorry no we don't do that. So how to you go on without a phone for that period?????