VVM debt collectors

I got a call from VVM collectors regarding the Vodacom contract , in my surprise I don't even have an account with Vodacom they said I owe money on the account I don't know when I asked them to send me a signed contract and all the documents cause in my experience you won't open an account without signing the contact.

I was told to write an affidavit send my ID copy and sign it 6 times on my ID copy so that they can check if it's not my signature on the contract. I got furious cause I don't even have a contract with you.

I got an SMS from them that stated: "Please call VVM on *** to discuss your Vodacom account, ref I*** Alternatively send us a WhatsApp https://wa.me/*** or email ***"