Unknown R99.99 Debit orders

Last year in November if I'm not mistaken I discovered R99.99 unknown debit order on my bank statement and I reversed it. Even on the following month same thing happened but then the narration was different on the bank statement, this continued until now when I called Standard Bank to give me the details of the company because the narration on the statement only states BILLION. The lady I spoke with on this number *** said they are collecting for various companies & she said she needs my number to log a request to get full details on what this debit order is for but I did not give her my number because I don't trust this whole thing now. Please investigate this further because I did not enter into any contract with this company or else I will take legal action against the companies involved because I can see that this is a ****. The reference number that appears on the statement is RF***5BIL*****5