car wont start at gas station. needs new emission sensor

I made the switch to a new vehicle, with added warranties 2.5 years ago to avoid the used car dilemmas I was having. Well, at 11,000 miles I need a new rear shock, - warranty. At 19,000 miles I had no heat due to NO coolant, cracked water pump. Replaced the water pump --factory warranty. My vehicle has had a few recall issues addressed. Last week it was in for the Battery recall -- new battery. Two days later, my check engine light comes on..... Took it in yesterday, (along with an oil change--prior oil change sticker still on window) I was told that the emissions sensor has to be replaced, "don't worry, you have the factory warranty".. by the way has it been hard to start after filling at gas station? Running rough?" NO, not until this morning. It took numerous tries and started like my flooded '72 Chevy Nova did back in the day. That car was easier to take care of, I will tell you that. Now, I have been told I badly need new brakes, with rotor replacement, $800 some for cost. At 28,000 miles????

Has anyone else had this? Granted, majority of my driving is city driving, --- stop lights.

$800???? I am supposed to be getting the emissions sensor replaced, tomorrow. I feel like I can't trust this vehicle and IF I can afford to take a road trip home this summer/fall, I should rent a car. WHAT A JOKE. Note: all work has been done at dealership I bought it from. Service department has been accommodating, but I have to do my homework and ask questions.