MTN Upgrade and Mondo

I upgraded my MTN contract on the 28th of March 2022 on the offer that MTN had for a S22 phone with free galaxy buds. I got confirmation of the order on the 4th of April 2022 - Reference nr ***1. I received the new phone only today - the 16th of May 2022, but with no galaxy buds. When I phoned MTN they said I must contact a company called Mondo that handled the upgrade. I phoned them and the first lady I spoke to said I must go to the Samsung members app and redeem my voucher for the galaxy buds - well, there is no voucher to redeem. I have called Mondo now four times, each time holding for a consultant for about 10 minutes, and when I got through to one - she put me on hold again - after 5 minutes I put down the phone. This is not acceptable to me. MTN gets you to upgrade with special deals and promises, but they don't keep to it. I have requested Mondo to call me back, with no avail and MTN is of no assistance.