I have made my payment for my internet and sent proof of payment , yet they keep harassing me with emails saying I haven’t paid yet those emails are no reply emails so I really want to hear from them as to how are we supposed to send proof of payment wher

I have made my payment for my internet and sent proof of payment , yet they keep harassing me with emails saying I haven’t paid yet those emails are no reply emails so I really want to hear from them as to how are we supposed to send proof of payment where they can find it because clearly on the email I was provided with by one of their agents is not a valid email, they give you a reference when making payment why don’t they use that reference to check through the payment they received if your payment is not one of them. Their app shows that I have paid and it malfunctions and says I haven’t paid again so I’m really annoyed at this point and would like this matter to be attended too ASAP!!!