what spider said. highly unlikely RM have been used to send out a return box. is there contact details on the VM letter or whatever it is? if not you could take the equipment and VM letter to your local HQ or pack the equipment yourself and create a return label here
http://www.collectplus.co.uk/returns...from_postcode= and post it out.
if you opt to send it via collectplus then be sure to put a letter in the box just stating its a return and put your customer number in so they know its from you. also be sure to get the tracking number when handing it over in a collectplus shop.