First of all, my condolences. Staying in an unpleasant hotel room can be dreadful.

I don't have much to add to the previous (excellent) post, except for the following:

Speak to the hotel manager before you do anything. I wouldn't taunt him, but respectfully remind him that two months' worth of business is riding on this and it's in his best interest to sort this out.

I know it's annoying, but you might just have to switch rooms. Prepare yourself for this possibility.

Don't contact your manager in your home country until you've run out of reasonable options locally. You run the risk of looking weak if you show that you can't deal with a simple problem like getting a new room in a hotel without his/her help.

If all else should fail at this hotel, then I would contact my manager, explain what the problem was and what I'd tried to do to remedy it, and explain how the hotel's management were unable/unwilling to solve the problem. Only then would I mention changing hotels.

Best of luck to you.