Unauthorised debit on my account

<p>I found this loan service online call loan detector and registered with it thinking would help me with a loan, but before 7 days ended I changed my mind and called hem on ***to cancel that was on the 13 November at around 9 Monday and I spoke to some guy and they said it was cancelled , immediately I got and sms with ref ********** 272581 confirming cancellation. now today 30 November 2017 I got a debit order for R395 with reference credit gain - ********** -LFSA-171130 I need it reversed ASAP Please help</p>