I understand the principle - complaining about bad customer service.

However, you were going to get something for free. To complain about that in such a manner is a bit childish. There is also a chance that those posters are not suppose to be "given" to anyone - customers or store employees.

To ask to be reimbursed for a gift card you purchased - did you give it to someone? If you did, you gave them a gift and it is theirs to do with what they want. If you got it for yourself, give it to someone as a gift or donate it.