Poor service

I was called by Mtn’ outsourced company called Rewards Co. I did an upgrade through them and waited for my phone to arrive. 7 days went by and I did not receive my phone and my contract was not amended. I have since called Mtn over 5 times and given over 4 other numbers to call. Mtn does not have any authority to complete the upgrade (as its incomplete on the system)??? Rewards co won’t do anything without my ID number, which I won’t give them with the huge amount of *****. They won’t take my details or call me back to look into the problem. Will anyone notice the incomplete work or take ownership?