1 week only and cancellation is nightmare

Acquiring contract online from MTN is a ****.I was clear with my coordinates and only after I teceived the 5G router with no connection the agents tells you that no connection. Been trying to cancel for weeks now with email to *** and customer care with no straight forward answer.Now instructed to take the gadget back to any shop to get ref number which I pray dont accept because I going to loose it.