Suspicious/ Bad Customer service

I have an active contract with Vodacom but October 2017 I took out a contract at Cellucity Canal Walk, the phones lasted 6 months, these are Iphones. We have relatives who have similar phones and its still working. They then proceeded to fix it wanting me to pay almost R 5000, I have tried to reach out to their head office, their response was that sometimes these things happen. I am paying for two phones with limited functions which are still by the store, they committed to have it delivered its been two days now and Canal walk in 10 minutes away from me.