Wow. If you've had no service at all, they owe you £8.40 a day, so around £170, and instead they're charging you for fixing their broken kit, and charging you for failings of their new payments system that has repeatedly marked direct debit customers as "overdue". So glad I'm no longer a customer.
Usually the helpful forum staff can sort this out without you having to deal with the poor quality offshore mumblers, although don't expect any credible goodwill offer for the company's multiple failings - VM's policy on goodwill payments is laughable.
If they can't sort all of those three things out, or you think you're due more compensation then make a formal complaint to VM in writing and sent by recorded post. VM's complaint handling is to the company's universal standard of excellence, so start on the assumption that it will be fobbed off or ignored, and you should read and follow the guidance from Ombudsman Services to take the complaint to adjudication.