I can see you being irritated that this happened. I can even see you deciding not to patronize this particular Borders. I'd probably be right there with you that far. Heck, I can even see this incident leaving a bit of a bad taste in your mouth, souring you on Borders in general. What I cannot see is you telling the manager to tear up your Borders card in some kind of gesture of pique, and then writing an angry letter asking for reimbursement on a totally unrelated purchase.

Free posters just don't strike me as important enough to justify all this. That's just my two cents though.