Fix due date of fiber invoices!!

I have asked Vodacom before to correct the due date on my fiber invoices, and they won’t!! E.g, the statement says fiber is from 01 May to 31May but their due date says 30 June which is wrong cause in the past my invoices for the current month would always be last day of the month, because if I don’t pay by the 7th of the following month then I’ll be listed as not having paid the account on time or having my accounts suspended, please fix my invoices!!!!