#Item paid no1

I have been billed "#Item paid no1" since 2016, it's frequent recently, whenever i talk to their team of bankers, they don't help but insist the problem is with me, every time i make a purchase i always make sure i have more than enough balance to cover the costs, but every time i see this charge claiming i made the purchase without having enough money so they covered for me, i explained many times i have switched off the overdraft option in my account.. still no help... i have tried intentionally to buy airtime with not enough balance but has always rejected because there's not enough money and I'm billed for that.. which doesn't make sense to me that they would honor purchases that require more funds than airtime!