Herotel suspended service that has already been paid for

Herotel suspended my service after i paid my for my services. I was told by a consultant that i could pay for my services on the last day of the month. Ever since I've been with Herotel i have been paying for service delivered on the last day of the month. But ever month without fail herotel emails me about my payment being overdue and threatening me that they will suspend my account. Im now sitting without fibre but my fibre has been paid.