Dunkin Donuts

So, there is this Dunkin Donuts close to a high way ramp near my house that I go all the time. Today was the third time they messed up my order. I usually get my Ice Caramel Lattes right? But they keep forgetting my caramel, and give me regular iced coffee but charging me the latte price which is a little more that an iced coffee. It sucks because you sometimes don't know until you get home. Anyway, Today was the third time they messed up in a little over a month. I went through the drive thru and spoke into the speaker my order, and then I heard the woman repeat it back, and she got it right, but how could she forgett the caramel?? I don't get how they can get it wrong when they repeated the order right.

Unless they are either ripping us off by charging us more and pocketing [not them personally but as a company] the rest. I go there because it's the only one that has a drive thru and I'm usually tired enough after work to not want to walk in the store xP. But my point is, three times in the last month or so? 

Also the lady who handed me a drink gave me a 'tude because I asked for a receipt?! I'm on a budget, so I like to keep track of my purchases, thanks, is that too much to ask?