Telecom 1023

I recently dealt with this company telling me that they were calling from TELKOM, in which our company does have a Telkom account. They sent me a few mails which I just deleted and then they started calling me repetitively to "follow up" on the paperwork. They asked if we can please fill out the form in which I said that we are not interested. They guy went on to say that it is just to updated our company details and there is no cost to it. I said I will do it and I took long to do so, so they called back days later. I eventually signed the form and sent it back and heard nothing. Today I get an invoice of R14 400 that must be paid IMMEDIATLEY?!?! I thought there was no cost involved?!? The lady argued non stop saying it is due to my negligence and that the ads of our business are already running and I cant opt out of this contract. Her name was Leti and I continuously asked for her website so I can have a look and she said she will email it to me in 2 minutes. I refused and said I want it now to check and she said no I will send it in 2 minutes and hung up on me. Its almost 30 minutes later and I received nothing. There isn't even banking details on this invoice. She says she will give us until Monday to pay the invoice in full? Now I Google them and see people explaining their experiences word for word like my story and its our fault yet they're the ones ****ming people? These people are a joke and total ****MERS!!!!