It was always made clear that the Mechromancer character was a pre order bonus as well as the Premier Club items.
The Season pass was spelled out as covering only the 4 planned additional DLC story content, and nothing else. Randy Pitchford has gone on to tweet that there will be additional non campaign offers available the will NOT be part of the season pass.
For Pear 21, if you have one of Best Buy's reward memberships, they can just look it up for you thru your account and reprint the receipt. If they have an email address attached to the account they can send it to you that way. For me it was printed on the receipt and emailed as well.
If you don't have an rewards zone account, I would recommend the Best Buy Rewards Zone community forum.
http://www.forums.bestbuy.com/t5/Reward-Zone-Gamer-s-Club/bd-p/gamersclub
Last year when BB had a program where if you bought 5 suggested games of a list they gave you a $100 rewards zone credit, it went horribly wrong. Many of us used the forums, and the people working there ( they have -BBY next to their names ) were very responsive and resolved issues within 24 - 72 hours. Better than dealing with customer service that often has no clue or concern about gamers.