Payment at fault

I have been their costumer for a very long using the same method of payment that I am using now i never had a problem except early January 2024 that I didn't pay December usually by that month we get paid earlier so I made payment 14/12/23 They called almost every day and I send them that at my workplace we are not allowed to answer our cellphones they rather answer on my email and another thing you can't just respond to any call there are ****s out there and January 2024 i paid on the 29/01/24 they say it was late it was even not month end and i can't just send proof of payment to any one without any proper conversation and contact details Thank you

Thank you