Suspected MTN/ DSV *****

My spouse have been due for a contract upgrade . She upgraded via a contact centre and were suppose to receive her device . She never received the device as DSV couriers have excuses in delivery the device . Numerous calls have been made to MTN and nobody could assist. MTN has now deducted a debit order for the device my spouse had never received . We are very frustrated as we don't know whom to contact as the call centre's send us from pillar to post . DSV at a stage came with the upgraded device . After my spouse signed for it they claimed something is wrong and didn't give the device to her . MTN had know debited her account bit she didn't receive the upgraded device . Please help