Losing customer payments?

I made payment for Vat and Duty but still receive notification my parcel can not be released as payment is due. Payment was made via the payment link received in the mail they send. The support whatsapp is no use at all. I emailed them proof of payment three times already. Then they mail back giving me a different email that POP needs to be send to but when I enter the given address, it gets kicked back stating address does not exist. I even tried adding proof of payment to the link (as stated on their site), using the camera via their site but yet another error message stating file to big. SERIOUSLY?!!! I need Buffalo to investigate and a REAL agent to contact me! This is unacceptable. Very poor service!