Wrong deduction time and now account in arrears

Last month on the 26th before I got paid Medihelp deducted my monthly medical aid that should have gone off on the 1st of July. They have previously on the 1st of June already deducted the amount for June. I phoned them on the 27th and they said that its a technical problem on their side and they will correct it and let me know of any amount that will go off. I have received no communication in that regard instead I received communication that apparently my account is in arrears since June and apparently I owe dubble the amount. Medihelp used to be so good until now.