If you were a weekly fixture mostly on your own dime, I would continue being a weekly fixture and still asking the same kinds of questions. They are asking that you not do the shop for 2 months. If you disappear for 2 months and then return and the shopper they think is you again, you could get disqualified from doing the jobs further. So in your 'two months off', treat every routine visit as if it was a shop and when they 'nail you' the MSP will know they are in error.
I have never been disqualified by being identified by Bestmark or anyone else. I would expect that if I WAS conclusively identified, I would be told, not paid for the shop in question and not allowed to shop the location further at all.
What I suspect is happening is that the client is seeing too many reports that are very similar (from you) and is looking for fresh eyes.
As for payment, I would give it a couple of days because a lot of folks turn a 3 day weekend into a 5 day vacation so manpower shortages are frequent. Banks and Post Offices are closed for Columbus Day, as is the government.