Unfair service

On the 21st of September i bought roof material from these shop, they never had it but they promised me it will be delivered as soon as they receive it, today on the 30th of September i called them to hear how far they are the manager (Andrew) told me how expensive the roof turned out and i must come for refund or put more money for me to get the roof. Please help me in this process. *** that is my contact number.