It sounds like they may have been expecting the SLK to come in and be available to you but it was returned late or whatever. Could be a host of reasons.
I'm not sure I really understand the logic behind walking away from just taking the SLK over $30. I completely get that it's really frustrating but I would rather spend my vacation time on vacation. I'd have spent the $30 (assuming it was just a total amount and not $30 PER DAY?) and then complained, complained, complained to claw it back after I get back from vacation (and can complain during my work hours
but I understand that's just me.