What's now wrong with my 2005 Ford 500?

2005 Ford 500 was running fine until Ford dealer did an oil change, replaced air filter and tried to sell me $1000 more "services". Since then it has slight to severe hiccups when hitting brakes and/or when going down the road, especially on small hills.

Sounds as though a sensor lead has not been refitted.
A scan will check for fault codes. As it's only occurred after the service we ought to refer back to dealer.
May be an idea to get scan codes first as dealer may suggest it's nothing to do with them and charge you the ' extra' money you declined saying they did say it needed more work/ parts.
Check for self for all connections. Try and find a trusted? Local garage who can over check and give better understanding of fault(s)

Republic MO Ford is denying it had anything to do with them. Scanning is going to cost me minimum of $60 plus labor to correct what Ford obviously caused. All the $1000 they tried to get was services ie. Engine coolant flush.

Take the car to an auto parts store and have the codes read, that may give you some idea of the cause. Failing that, I'd focus on either a disconnected wire or something fuel related. We don't know for certain what you're describing as a hiccup but assuming you mean a miss, most likely it'll be related to either fuel or ignition. Strange that whatever it is acts up when braking too, that's odd. One of the suggestions the dealer made wasn't a fuel filter was it? How many miles on the car and has the TB ever been cleaned?