Budget facility or ******ion

During December 2019 my wife had purchased an xbox as a Christmas gift for my son. We opted to charge it on our budget facility on our absa credit card over 6 months only to discover that they had taken off the entire amount from her straight facility. We then thought that maybe they didn't charge it correctly to a budget facility and maybe it was a blessing in disguise cause we would be paying more interest using the budget facility. The very same month they also debited her credit card with an installment for the same item and they have been doing so ever since. This to me makes absolutely no sense because what is the use of charging an installment if they initially took out the entire amount for the item in the first place. After consulting with many call centre agents and even going physically into a branch we are left non the wiser....It's seems that we have paid doubled the amount for the item plus interest and Absa thinks that it's just ok...we are living in difficult times and every cent is valuable...this is not rocket science and only takes commen sense to figure out. What amazes me is the lack of competence shown by Absa staff members... PLEASE RESPOND URGENTLY.