Internet down indefinitely with Vox

Fibre was installed in early April and abruptly stopped working over a week ago. After a total of over 10 hours on the phone, two visits by technicians, one from Vox and then one from Vumatel, Vox has now told me they have no idea what's happening and I must wait for Sales staff to come in on Monday. I haven't the faintest clue why Sales has to be involved in fixing a faulty connection. I'm pretty sure that the quickest way to get connected is to cancel the Vox contract and go to a new ISP, no-one their seems to have a clue how their own network works or how to fix anything.