Bad SERVICE

I am disappointed in the services I received from MTN and Mondo, I have used MTN for than 15 years and recently ordered a phone via their online service, this phone was an upgrade and the wrong phone was delivered, since then i have been taken from pillar to post by MONDO and MTN, MTN says they cant help me get the right phone and that I will be billed and MONDO is telling to go to MTN none of the stores near me can take the phone because they are not a direct store, when finally got hold of MONDO they said they will collect the phone and its now been 2 weeks. I don't understand why I have to pay for a phone I don't have. Till this day i cannot get through to MONDO and I am waiting for them to pick up the phone.