Suspicious staff

I have app**** for an account and was contacted by Lewis in Kimberley and I was told my application was successful. I went in signed the the contract and purchased a bedroom set. I paid deposit and after month my 1st installment was deducted as I have signed a debit order. The following month the debit didn't went off and I received a call from the stored stating my account was declined. I was in shock because I already have the goods and paid 1st installment and I told the lady whats going on and she explained the lady that put my contract threw **** a mistake. I told them its fine I am gonna pay but I need an account with installment and bank account detail but she insisted they have to collect the money cash and that sounded to me in suspicious. Myself and my spouse received numerous calls and we told them how am I to pay without an account number. I have received a call from a lady stating she is phoning from Lewis collections and I have explained I am waiting from the store to send me info via email for me to pay the account but to date nothing, the collections lady threatened me that they gonna come with police to collect the bedroom suite and I told her we will see and that she will not threaten me because I never refused paying account and we got into a quarrel. I need someone from head office to assist regarding this matter because I need info how to go about paying the account and the installment I have to pay monthly because they want me to pay the outstanding amount in full and that's ridiculous.