Vumatel unable to resolve my Fibre problem

I have been experiencing a problem with slow speeds on my fibre line which I reported to my service provider. They logged a call with Vumatel who came out to my site to check the problem. I was told the ONT device was faulty and they replaced it. Waited for it to be configured but nothing worked. They came out again and replaced it again. Still nothing. Vumatel came out again and replaced it for the third time but still unable to get it to work. They spent half the day trying to fix the problem but did not succeed. Im now left with no fibre for 4 days and I don't know if or when they will be able to fix it. The technician said there is nothing more he can do.