I used a very small drill, and drilled 3 holes into the plastic strip about 1/4" apart. I then reassembled the strap. I threaded a needle with Coban thread. Coban is so strong I can't break it with my hands. It is used for outdoor awnings and other things. I sewed the Coban thread in and out of the holes, through the outer cloth, then foam, then the plastic holes, foam and the bottom cloth and then tied it off.
The cloth on the outside was not torn, but stretched way out of shape. I found some iron-on patches, and wrapped the strap with the iron-on, and sealed it on one edge. That covered some of the thread and all the wrinkled strap material.