Incorrect product delievered

I ordered a neoprene bikini in December off Groupon. This is obviously the product I was expecting. It arrived and was not neoprene but normal swimwear fabric. I immediately inquired on 18 December about receiving the incorrect product . I had absolutely no response but received a 'How would you rate the support you received?' on 25 Dec (yes, Christmas day). What service? I hadn't heard a peep out of them.? In the meantime I wore the bikini because I'd ordered it for the Dec holidays and couldn't get hold of anyone. I still hadn't heard a response in January so put it down to it being the festive season and sent a follow-up on 11 Jan. I then eventually got a generic response that was completely unhelpful. I asked for an explanation and then still received no response. Sent another 3 follow-up emails over the last month and still no response. I eventually tweeted my frustration and was given a separate email address to send my query to. I got a response from this email address but the person I dealt with was also rude and unprofessional, passing the blame onto the supplier. They refuse to accept responsibility. Absolutely appalled by this experience.