parking in a disabled bay

Hello, could someone advise me about a parking ticket from UKPC, i parked at the Metro centre in a disabled space but when i have closed the door my disabled badge must have slipped from view or my husband could have knocked it off as he has to struggle to get out of our car, we only went in a furniture shop when we returned the parking notice was on my car stating pay £60 or £30 within 14 days as failing to display a valid blue badge clearly, the girl in th\e shop said the were putting them on lots of cars even for touching the white line, do i have to pay this as we do have a valid badge, thank you x

parking in a disabled bay