Sorry to hear about the calls causing you to block the number and can understand that it's frustrating. If you haven't already, please see the advice in this thread such as ensuring the marketing box is unticked in your online account to prevent future marketing calls from Virgin Media.
Sorry, don't have time to look through 17 pages from a forum to stop those calls. I have been a software engineer/web developer for over 20 years and 10 minutes on the site didn't find any option about marketing except the one that looked like I already checked years ago. Number is blocked via phone. Employ some real programmers rather than lame frontend artist/engineers and marketing people who demand stuff infeasible.
RANK BEGINS: It reminds me of the last company I worked for who forced marketing assignments on programmers and used frontend javsascript people with no idea how to use logic or program and problem to hack the site to the way marketing wanted, demanded by their bosses above who didn't have a clue how a website works. Artists don't belong on making websites as they have no logic, but marketing love them because they do what they say and really screw up websites with hack after hack. RANT OVER