MTN reward co

MTN Reward co is failing me, I applied for sim only data in the 22nd of Oct 2026 and they delivered the SIM card in the 27th Oct until today the sim card has no network. I tried calling them several times to either cancel the applications so that I can apply in-store, they always say there is no network, I even went to MTN store still they couldn't assist me because the case is for Reward co. I have already accepted the mandate. I just want them to cancel this sim once and for all.