MF does have a certification page but I don't know anybody who has ever taken any kind of certification for them.
I don't think the length of time you have been working for them is the reason you are blocked from the fast foods. The fast food shops are usually immediately available to new shoppers in all locations - unless the shopper provided some information when completing the profile that makes the shopper ineligible for the fast foods. Things that might make a shopper ineligible for the MF fast food shops:
- The shopper was employed by a fast food company within the last 5 years
- A relative, friend, roommate was employed by a fast food company within the last 5 years
- The shopper has dietary restrictions
- Shopper is a vegetarian - the MF fast foods require that certain items be ordered - vegetarian options are not on the list at most
There are a number of other reasons a shopper might be blocked from the shops. Only MF could tell you why you are blocked. I would suggest you ask again, but MF is very secretive about how and why they make their decisions so they may or may not tell you.