You say, "My TV still isn't working now over 14 days.. error code 7400.."
That error code means your set top box hasn't been activated. Have you checked and followed the help pages for tv-error-codes/7400 ?
It may be a problem with the backend systems which they can sometimes rectify over the phone, or they can either send out a replacement box or engineer.
Have you called 0800 953 9500 to activate the box? You will need the box serial number, and your account number and area code.
You could also try contacting New accounts and Set Up for them to complete the setup and activation. That would be options 1,1,1 and 4 if dialling 150 from a Virgin landline , or options 1,1,2 and 4 if dialling 0345 4541111 from any other phone
The Service you do for others is the rent you pay for your room here on Earth - Muhammad Ali
Thank you for reaching out to us in our community and welcome, I am sorry you were having issues with your TV service, I have had a look our end and it looks like we have already helped with this, can you confirm everything is now set up?