Vodacom collections

My vodacom account was handed over to Allienceserv for collection, after multiple attempts to get a settlement letter as i’m now in a position to settle and close this account, allienceserv has not been cooperative, they keep telling me the amount over the phone but cannot send me an email for record purposes, they just wanna give me an amount and for me to pay into an account number they give me on the phone, what if it’s a **** and i pay my money into a wrong account and get ****med, only for vodacom to come back to me that i’m still owing them? Vodacom needs to cut ties with these fly by night debt collectors, please can someone assist me with getting through to the right people to assist me with settling this. Allienceserv are chance takers. I want to settle vodacom and clear my name.