Hotel Booking

I booked 7 rooms with BookMyRooms.com.  I was very happy at first because They had the hotel I needed at a very low cost.  I was booked at the Las Vegas Hilton for the Jewelry Tradeshow. 6 of our rooms checked in on that thursday but my boss was suppossed to check in on Friday. Friday morning my boss called and said that he could not make it and that he was going to be checking in on Saturday instead.  I called my sales rep which he said was no problem but when he confirmed the changed he said the hotel would not refund that day. I know it was last minute but I got charged for a night we never used.  I then went to the hotel manager to explain our situation. after aguing for an hour the manager agreed he would refund me for the one night we never used. By this time it was past 6pm so I waited to call James and inform him that the hotel said he would credit us.  James said great and said he would call me back. I then got a call back and James said that when they called the hotel the hotel denied that they were refunding bookmyrooms.com. At this point I don't know who to believe because the manager I spoke to could not be reached but I am going to complain about the Hilton as well until I get reimbursed for the night we did not use! Next time anyone finds themselves in my predicament please get it in writing.