Brake pressure

So I too my car in to get the pads replaced last
week. After that my brakes were smoking so I took
it back and they said there wasn't any problems. It
did it again and they said the brakes are just new
and will just burn a little until they fit right. A week
later it is still happening. Here's what I've noticed:
Over distance the pressure increases - like it starts
braking without me pushing the brakes after a
while. It's just my back brakes (the ones they
replaced which are disks)
At higher speeds they squeak (I think this is
because my rotors need smoothed out which I
paid for and they didn't do).
When I get to work it smells like they are burning
and the parking brake has much more resistance
when I pull it, so it must be building up pressure.