Black Friday 30gb deal

Seems they can't get there act together. Only received 5gb instead of the 20gb. Won't fix my account, they request to see the signed contract but Mtn cresta store can't provide me with my contract as they apparently don't have it with them. Am I just going to be paying for something I didn't sign up for? Worst thing is if you reverse your payments they want to blacklist you. Why should I pay when I am not receiving the product?