Two things:
They trick you(Yes, trick you!) into purchasing a subscription that's cleverly designed to pay more for a longer period of time compared to the closely follow up subscription priced just below that for one month.
They also duplicate month old messages that you've already seen(Note, at this point your subscription is cancelled) to make you think you have new messages from new people so you decide to sign up for that subscription once again.
Well, guess what... They played you again!