Poor service

Good morning. This is very stressful situation, the company known as "Mondo" offered me a MTN sim card but the simcard is not registered on the network (MTN) even if I try to get hold of them I fail since I not provided with any contact numbers.

The sad part is that I already paid for the sim card and debit mandate accepted too. But the sim card is not working at all.

I receive a sim card on 29/12/2025. Please assist me to resolve this matter.