I would like to upgrade to 20MB, but when my NTL was first installed on the XL package, the best speed I could get was 4MB, this was despite having a new fibre cable dragged through from the main junction 150mt away.
I had to endure nearly 10 weeks of telephone calls and bad service before my problem was resolved, (not to my satisfaction). I had to be settling for a downgrade of my XL package for my internet connection.
My main concern is that if I opt for 20MB will I have to jump through the same hoops if I cannot get somewhere close to this speed or is it now routine to get a more reliable and faster download speed?