Poor after sale service and information

I pre-ordered my phone on the promo that gave an evoucher with the phone. I received the phone great service there, but no paperwork, no instructions about the new number or how to activate, no email to give the latter either. Tried to phone call centre's, not much help there. Trying to avoid going into stores to minimize contact with people, and I can't seem to get anyone to tell me where to get the evoucher from, or what it can even be used for. The after sals customer service part just seems to not only be lacking, but be totally non existent