branch states i can not return my phone within 7 days

Im heart broken i purchased the huawei p50 from Telkom, I've been having problems connecting to my 5G network at home. The contract was taken on Saturday and i tried having to return the phone for another phone, mind you this is all within 7days.

I am told that i can only change the phone to a huawei, i really am discouraged and don't want the phone as i do not know what future problems this brand might give me. I don't want much i just would like change my phone to a contract phoned i would be helping about.