payment deducted twice and only received airtime once

<p>we are new clients to intellicell with cell phone contracts.</p> <p>we made our admin payment of R300 on 24 Feb 2016 and then we received our phone with airtime on for the month of march, 1st installment of R299 on 24 Mar 2016 we received our airtime for the month of april. 2nd paymnet 23 apr 2016 and then we received NO airtime for the month of may. now it's time for the 3rd payment our bank gets debit not once but twice???????? phoned in about it but no one can give answere to how or why???? i have the proof that my paymnets are up to date and that i have not skipped any payment></p>