How do I tell my sister and her husband to stop using my Amazon account?

They can watch stuff on Prime video I don't care about that but now Amazon took the monthly subscription fee from my sister's card because there was an error in my card and then she asked them for a refund and they canceled the entire thing and now I can't watch Batman tonight and I can't subscribe from the phone app because my card can't be used on the play store due to a weird regulations thing in the Egyptian banks. I can only subscribe from the website which will have to wait till the morning.

I don't understand my sister I could have transferred the fee to her 👀 it's actually very cheap like less than the price of a coffee in a café it's not worth all that. I'm confused but I seriously want to take my account back.