Marriott Bonvoy - you do the work and you don't get the reward

The Marriott Bonvoy loyalty programme is such a let-down. I stayed various nights in Marriott hotels and upon check in, provided my Bonvoy loyalty number. My stay for some nights were not recorded. I called the Marriott Bonvoy Contact Centre and was informed that I have to get a copy of the bill from the hotel and send it to the Marriott Bonvoy Contact Centre.

How ridiculous is this? I have to do all the work in spite of giving my loyalty number when I checked in. I am expecting that my loyalty number will be recorded and that I will be allocated the loyalty points. But this does not happen.