Yep had the same problem and same modem specs, It's a pitty VM didn't bother asking me or finding out if my modem was cabable of 20meg when they upgraded me!
Countles calls and the same BS... but once I mailed tech support UK and got someone in the Uk, it was a totally different kettle of fish.
Straight away they said "no way your SB modem can handle that so here is a new SA Webstar in the post" 24 hours later it arrives! 20meg cable ever since, pitty I have to move now and go back to ADSL
Satisfied yes you can be, but VM should have done their homework before taking over another ISP and just basically asking...whay hardware you ahve before allowing an upgrade.
Keep VM Tech support UK based peteition i think is needed.
Always got a decent straight answer or information,on the few times I got through to Uk and not diverted to the sub-continent.
Always been thumbs up for UK side of support.