Cheats. Awful.
I made a reservation through booking.com for an apartment in Gdansk with Gdanskie Apartmenty, which included free cancellation before a certain date. Shortly after making the reservation they took a 30% deposit from my credit card. No problems with that.
Unfortunately, about a month after making the reservation and about 2 months before the free cancellation cut off date I had to cancel. They didn't refund my deposit.
About 2 weeks later I emailed Gdanskie Apartment asking for a refund and they did not refund me or even reply.
About 10 days later I sent another email and received a reply from "Marek" who said he would refund me in 3 days time (after the weekend). No refund was payed.
About 2 weeks later I sent another email asking for a refund and "Marek" promised payment that day. No refund.
I then complained via booking.com, who contacted Gdanksi Apartmenty who again promised to refund me. No refund was received.
I then raised a dispute with my bank who temporarily credited my account.
About a month later Gdanskie Apartmenty resubmitted a request for payment to my bank, and I had to dispute it again. I finally have my my money back from the bank some six months later. Do not reserve an apartment with these cowboys.