I have spent a couple minutes and rescind the offer of new belts for you.
THIS IS EXACTLY WHAT I DID;
In a bucket of hot water with some dish soap, immerse the belts in this pail, let them first soak for ~half hour, then take a stick, spatula, or breaker bar - idk what you have, and agitate the belts for a few minutes. Notice how dirty the water is - that is what stopped the belts from operating correctly.
If you have clothes pins, use them to secure the belts when they are fully retracted - pull them out; use the pins to secure them. Put the belts back into the bucket with fresh hot soapy water, and let them soak again for a half day. Stir them up/move them around once in awhile.
Take them out and hang to dry. Leave the pins holding the belts out.
They will be as good as new, and work perfectly.
It's what I did, after I bought a pair of belts for my vert GT. I could've saved myself one hundred bucks if I had of thought it out before I started. So easy and worked out soooo well...