How do I tell Photographer you want a new one?

Keera03

Wrote this out already but I think I put it in the wrong catogory so here it is again!!
Last month me and my fiance went and got our engagement pictures done.. we paid 300 dollars to get these done and they turned out completely awful.. I had a double chin in every picture and I don't even have a double chin. So this made me freak out because I do not want my wedding pictures to turn out this way. This surprised me because my brother had used him for his wedding and the pictures were all beautiful and I have seen his other work and it was fine...I already paid a 500 dollar deposit to this photographer and I am now 7 months away from my wedding and want to change photographers. How do I tell this photographer I do not want him to do my wedding now? or should I just suck it up and hope that he can deliver good pictures?I don't want to sound rude or superficial, but I really do not want to waste my money and have bad wedding pictures.I need help how to tell this guy I no longer want him.