How can I fix belt slipping to the right on Proform Crosswalk 400E?

I bought a used Proform like my old one which we never had problems with. This treadmill looks unused. When we got it home and turned it on, we could not use it as the upper portion of the belt is over to the right. We turned it over and the guides are in place, but one of the heavy metal mounting brackets that hold the front roller in place looks to be banged/bent to the inside to close a space in between the mounting bracket and the roller. The mounting bracket on the opposite side looks straight and perfect. Because of this the roller sets off to one side and the belt runs up against the side. It appears that the bracket needs to be straightened so that everything lines up, but creates a gap of about 1 1/2 inches between the bracket and the roller on each side.