Be careful on payment links

I have been contacted by a company called Ver-tex who emailed me saying I owed money (which I was aware of). Within their email was a payment link. We used this link to make payment which it turns out, was never reaching Ver-Tex. I've paid over double what was due and it seems the link was to a PayU account. I am unable to get hold of PayU South Africa by phone and the only email communication is via nigeriashoppers@payu.com which looks extremely suspicious to me. They are no longer responding to my emails and I want a refund so I can pay the correct account directly.