Requesting high floor is just a stating a preference. Marriott's system clearly states "Guaranteed unless otherwise noted" and they have most of the room features, including the request of a high floor, clearly stating that these are just requests. I don't see why you would assume this would be confirmed.

When it comes to connecting rooms, this is not a room feature that you can request in their automated system. When the OP says that they accepted his request, what does that mean? Did the OP Ambassador reach out to them via email or phone and they positively agreed to connecting rooms? Otherwise, are we saying that they said "Yes, we hear you but we can't meet that request since we don't have connecting rooms?" Or, where they saying "We hear you but good luck to you. You'll get such rooms if we happen to have two connecting rooms available once you get here?" Maybe, the Ambassador didn't communicate clearly to the OP that (s)he just requested connecting rooms but the hotel did not confirmed that they would be able to provide these.

In my travels, I've requested connecting rooms a few times but I haven't gotten "acceptance" or "reassurance" that they would guarantee it. In the cases it was really important to me, I would make a note to call earlier in the day to speak with the front desk to try and secure these.