There are THOUSANDS of related patents dating PRIOR to the Voip-Pal patents, and if any of VPLM's can be cited as previously in use, somewhere, by someone, prior to VPLM then game over.
While there might be thousands of related patents I think one would be hard pressed to find more than a a handful that relate directly to RBR in VoIP.
The RBR patents that VPLM has developed are very specific in detailing the calling attributes over a dynamic network. Not many prior art pieces/patents talk to this at all.
Another interesting point I'd like to make is that of all the thousands of related patents and prior art documents out there both UNIFIED PATENTS and APPLE could only find 6 patents to challenge VPLM's RBR patent. SIX! I was expecting at least a couple dozen given the thousands of related prior art patents out there!