Roseville BMW Eric service guy tried to rip me off! Cheat me out of my money! Roseville California

Found coupon online, went in for 79.95 oil change, Eric was my service guy. The coupon was 79.95 for oil change and up to 7 quarts of synthetic oil, my suv holds 8 so I knew I'd have to pay for the extra quart of oil, and I'm thinking worst case 10 dollars, he quoted me 100.00 so was thinking extra quart and taxes, when I received the bill it was 106. And some odd change... I asked why, and he bumped it down to 100.00 out the door upon looking at the receipt I realized i was being charged 11.99 for an oil filter, clearly being a woman I feel he was trying to get over on me, I asked him, doesn't an oil filter come with the oil change at this point he was aggregated and agreed, grab the bill and then returned my 11.99 plus tax... But I was treated as if I had done something wrong. I will never do business with them again!