unauthorised Debit orders

I just discovered two unknown debits on my bank statement and when I traced them they pointed to fulcrum collections. I called them and they told me they are collecting for various companies and mine is for a company called Oversurance. I was like what??? they had to repeat this name cause I was my first time I had it. Two 99.99 debits by people whom I never spoke to. I was given this number to call and this number is forever engaged and sometimes it says number does not exist. mgdaline naidoo ***