Herotel bad service

Since Herotel took over HiTech the service and client services are not very good, they took 4 days to fix a problem with our network, and then bill us for the call-out fee - not sure what was wrong - they do not answer my mails? They said that we would only be billed if it was our fault? Would not mind paying the call-out fee, but days after the invoice, they suspend our service because of a overdue invoice. I phoned them before the time and said that we can only settle this invoice (R500.00) at the end of the month.