Breach of Contract & Faulty Device

My husband got a new MTN contract through Summer Mobile. Not even 3months into the contract & we started having problems with the device that was provided to us. The number for customer care for Summer mobile is the MTN 808 number. So we phone the number & is advised to take the devise to the nearest store. We take the devise today to the big branch outside Canal Walk the consultant looks at the devise & advise us that we need to take it to the Service/ Repair centre in Montague drive Montague Gardens. We get there & the consultant tells us, he cant book the devise in as we don't have the charging block and we should drive back all the way home to get the charging block & come back or we can go all the way back to Canal Walk to Samsung to have the devise repaired. This a devise that is just over 3months old. Then to top it all we explain to him that when the callcentre phoned my husband for the contract they gave him a fixed amount we will pay, however the bill has a totally different amount that we must pay & the papers we have has the same amounts as per the telephonic conversation and nowhere does it indicate the more expensive amount that is being debited off the bank account.