Unauthorised pre authorisation and the impact thereof

MTN engaged the services of International Call Centre to make marketing calls on their behalf. They had pre approved me WITHOUT my consent. When I asked how they obtained the information required to do so I was given the name of an institution which I am unable to find on line.

I require MTN, who authorised these people to act on their behalf, to assure me that this so called pre auth had no impact on my credit rating. I would also like the name of the leads data based used to obtain my information, so I can take this matter further.

I expect feedback at your earliest convenience and please be reminded that we have a right to the information requested, a right to know.