Rejected payment arrangement

Good day...I'm getting frustrated with calls that I'm receiving from Lewis Giyani by the post office. I explained to one lady that I can't mention her name,that I'm a sales person and I'm unable to take calls while assisting customers it's against the company policy.Then I contacted the sales lady that assisted me when signing up for the deal that I had issues with payments at work that's the reason why I skipped some payments.I told her that I would like to make an arrangement to pay on the 15th of this month of March,however the feedback that I got was that they want the money is in like yesterday and the 15th is no exception since I said I will make payments on the 25th. I really don't understand why Lewis is sent me an sms to say I should make an arrangement with my branch but the branch is rejecting the arrangement. I'm now getting threats that they will come and collect the goods that I bought from them and it's an instruction from the head office.I really need your assistance in making the with head office because I don't think I will go to the store anymore because of their unprofessionalism.Are there any other ways to make payments because they I was told last year that EFT is not advisable.I don't want to mention any names but I will never recommend anyone to that store,I mean why are they discussing customers information with every sales person in the store?I need intervention in making the payment arrangement for the 15th as it's the only time where I will be having funds.