They do not exist on the web nor am I able to contact them

I got a call from VDM Attorneys and would like to settle my account. I was told that I would be put onto a WhatsApp group and I could query the amount paid. I call back and the number I was call from is an outgoing line and I CANNOT find them on the web. There are several VDM's The number I was called from is 087 555 0248 and dialing it it say "The number you have dialed does not exist"