Frustrating

I am very frustrated with the accounts department. Every time I go to gym my tag would not work and always have to explain myself. Initially when I joined the gym I had an agreement to pay on the 20th of every month. I pay every month my monthly membership but I am always behind a payment so I went several times to gym company at East point to sort it out. They tell me it is their mistake they will sort it out, they happen to bill me on the first of every month that is why it shows as if I am behind on payment but it never gets sorted out so I am tired of taking time off work to ask them to bill me on 20th not on the 1st. Please.