BILLED 9 MONTHS AFTER INSTALLATION

I received a phone call from Vumatel last week. The lady from accounts accused me of not paying my installation fee of R1700. My installation has been done 9 months ago and I haven't received an invoice or any form of communication regarding this "outstanding amount" at all. The only invoice that I received, regarding installation fees, was from Afrihost, which said: "Vumatel New Installation R1007.77" and "Fibre activation fee discount R1007.77". Therefore R0 for installation. Please note again that this is the only invoice that I received regarding "Vumatel" and "Installation Fee". So receiving a harsh phone call from Vumatel, after 9 months is quite shocking and completely out of the blue. The lady confessed that I'm not the only person who is expected to pay my installation fee now and that I "must" pay it now. She claimed that they have sent me the invoice before and it must've landed in my junk mail (which I check daily) and none of the Vumatel invoices ever land in my junk mail, therefore, I think it's a terrible excuse. Having done a bit of reading on Facebook and this site, I've realized that a lot of people are experiencing the same problem with Vumatel. Their general customer service regarding this situation is extremely poor and they blame their clients completely for this instance.