Do you have problems getting the free mini in your GW store every month?

Hi, I recently learned about the free mini you are supposed to get at your GW store every month.

Last month I tried to get mine, and the store manager told me that it's only given on the first saturday of the month. I didn't read that anywhere but I guess it can make sense, maybe there aren't that many units.

So today, first saturday of december, I try again to get the free mini. The store in my city is a small store (Seville, Spain). The store opens at 11:00. At 11:15 I arrive at the store. There are 10 people inside, and when I get to the desk and ask, the store manager tells me there are no more free minis, just 15 minutes after the store opened. As I said, this is a small store in a normal city. Is this thing normal everywhere? Do the manager have to pay the free mini they give or something and he was stingy?