Sweepstakes Clearinghouse sent them $379.00 for a laptop never received and haven't got a refund they say they mailed Dallas Texas

Received a mailing from sweepstakes clearinghouse. I sent a voucher and $379.00 for a laptop. Waited about a month and called them to see where the laptop was. They said they were out of stock and would send as soon as more came in. Waited another week and called them and asked for a refund. Waited another few weeks and still had not received my refund so called them again. They told me they mailed it and to check with my post office. If they had to reissue another check would have to wait because they only do refunds once a month. My post office does not have my check. They keep giving me the run around. I am assuming by now that I was ripped off. Can you help please.

Theresa
North Adams, Massachusetts
U.S.A.