Unprocessed payments that don’t make sense

Really unhappy with how I would make a purchase on a certain date and be convinced that I paid for it, only for the transaction to go off 8 days later when I don’t have a budget for it. I don’t understand why this affects me as a customer and inconveniences my life. I thought the explanation makes sense from the lady who assisted me before, but it doesn’t add up. I would hate to have to move to another bank after 11 years because of this. I can’t have money leaving the account and I can’t make sense of it yet according to Capitec bank it didn’t and only did on a different day. Yet my balance shows a difference, I just realized it isn’t online payments only. I’m very unhappy about this