These worthless companies are persistent in that they are using a wide database of leased VOIP numbers & IP spoofing which masks their true identity. I imagine that they are also using the Federal Trade Commission's(FTC) DO NOT CALL Registry that we all signed up for as their cold call list to make calls. They do this because they know that the federal government is a lazy bunch of do-nothings that won't enforce jack. The whole thing is a joke.
I believe that the same cold call system is just being resold to another moron once it is discovered that the cold call system & equipment is a real loser.