Huawei

I took up a contract late October 2018, contract came with Huawei P20 Pro and a Huawei Y5. The Y5 only worked for a couple of hours after contacts were loaded onto it, I took the phone back in December for repairs it came back with the same fault so I didn't take it from the Vodacom repair shop, again in early January I was called to collect the supposedly repaired phone and to my dismay the phone was still defective. Again this morning I was called to collect the same defective phone, I do not understand why they want me to pay for a defective phone when I have paid for a brand new phone that I never got to use . Please Help