Wrong order, Mtn has claimed and sent me Cancellation message but when I go to the shop it's not canceled on the system.

I tried to buy a phone online, the lady who was assisting me kept on forcing me to take Huawei Nova Y72 all because she's using it. She insisted that I take that one after I explained I don't want Huawei anymore I've been using it, I want to change to Samsung. She then approved a Huawei Nova without my permission. At Mtn I called several times thy said it's been canceled but on the system it's not now I'm struggling to buy my desired cell phone. I'm so disappointed In your call center staff and your poor service.