Can I re-shape a heating coil that has been stretched out of shape?
The wire is nichrome. If it has not been heated, or kinked when stretched it can be reformed and attached to the high-temp insulators (hopefully the insulators did not get broken). Keep the coil spacing and space from the case so one area does not get two hot or short out. 

I have made heaters for industrial equipment with new wire, but once heated the coils get brittle and they tend to break much more easily. With a new unit and carefully repairing the coils you should be ok.