Have you done a postcode check to see if you are in a 500 area. I am also on the 500 package but my postcode is only a 350 area. Virgin only guarentee speeds of 250mbps on the 500 package so are fulfilling the contract by their terms if you are reaching minimum guarenteed speed. EVen if they have sold you a package in which you are not able to receive nor planning on upgrading. It is a case I am currently going through some 3rd party complaints procedures.
Thank you for reaching out to us in our community, I am sorry your new speed hasn't started yet.
When you changed your speed was it part of a package change?
When your package is changed and a new offer is given this is added on a 30 days notice which means the new package will not take affect until 30 days later, if you are not sure I advise speaking to customer care who will be able to confirm this.