<prompt> Human: So I go to a place called Pita Pitt often, and I always get the same thing, its 6.65 for the meal exactly, and I use a debit card to pay for that, looking at my past purchases through chase I noticed today they charged me 8.31, sometimes they charge 8.50 8.75 etc, most of the time its 6.65 though, and its always the same exact meal everytime nothing changes, the only assumption I can come up with is they are tipping themselves, but I dont know, can anyone help?Edit: the place is set up like subway, there is no waiterwatress or anything just a person behind the table, and they just put the food in the bread when I pay with a debit card theres a line to tip, and them being not a waiter or waitress theres no reason to tip them so I dont, and always leave it blank.  <response>: Bring it up with the manager so he knows its happening. You are not the only one. 