Unnecessary Arrears

I took a contract with Mondo on behalf of Telkom. My account was never debited in two months. Today i receive a call that i am 460 in arrears, only to find that the person who was helping capture my details never informed me that debit orders don't run on 25. Now they are calling and threatening me, this is definitely not my fault. I cannot take a blame for an *********** employee who rushed for a sale and did not explain. No statement, no calls. No communication from Mondo n only after two months they demand money. I spoke to Perrisha a supervisor and no accountability, no problem solving skill, no empathy. This is unacceptable