Unexplained brake humming after maintenance

I have gone to dealership in dayton for brake maintainance and they grind my back wheel disc too much and then it was making noise and i took it back to them . Then they did some adjustments to the front end and my car was totally off the balance. Then there was a humming noise coming from back wheels , so i took it to sears auto they said to replace bearings and i got it done still the humming noise did not go. Then i took it to the Same dealership they said they cannot help me. Then i took it to other dealership they said to replace the discs, then they did that . Still the humming noise did not go. Now i went to the dealership they said they cannot do any thing i have to bare it. Then now when i i back the car and slowly press break it make squealing noise. I took it back now they are saying to change the new pads which the first dealership replaced. I do not know what can i do?? So please advise me. Thank you so much . Where should i take my car next?? Advise.

could you explain some of your terms please?

“grind my back wheel disc too much” ? Rotors? then they should have replaced them.

“car was totally off the balance” ? what does this mean?

Bottom line, the problem is a squealing noise in the brakes? Other than that, the brakes work fine?

That happens frequently and can be fixed by use of a different type of pad.

Oh, boy!
Make, model, model-year? Advise.
CSA :smile_cat:

The car is Mazda3. 2011. And i live in dayton Ohio . I am fed up with these dealerships and mechanics. The humming noise in the back wheel it starts at the speed of 50 miles/Hr.
Thanks for your help

Does it make the noise only when you apply the brakes? You imply otherwise.

If it makes the noise all the time when moving, what makes you think it is the brakes?

repeat question:
“car was totally off the balance” ? what does this mean?

It makes Humming noise when it reaches 50 miles / Hr. And up. And when i Back up and press the brake pedal lightly it makes Squeeling Noise.
Off Balance I mean when i turn the car to left it feels one side is more tilted then the other. The steering is softer it does not feel sporty as it was original.The First Dealer did something to the alignment. The second dealership talked to the first one and they decided not do anything regarding this.
So i am confused what to do.
I will really appreciate your in put.
Thanks a million.