When the rubber of the CDS and/or the killer bars fail to adhere to the base of the cancel handle, and they don't have any rubber cement or other suitable adhesive available, clerks often resort to using rubber bands to hold it together. The result is what you see here, although yours is fairly extreme.
Here are two which are more typical:

Rubber bands were also used to make a "V" across the bars toward the end of WWII as a makeshift Victory message.
Less frequently, a staple is used to attach loose cancel parts.