Mods wont be back until later this week to help. (perhaps tomorrow). You could try live chat. To use live chat click support at the top of this page then choose the servuce you need supprot with (bill or pre pay. etc..). Click CHAT icon that pops up in the bottom right hand corner of the next screen.
There may not be a lot that can be done. Does the speed fluctaue with time of day? If so it could be just congestion on the line..
Cookie Vodafone Community Expert (or so I'm told) and S10 owner. I don't work for Vodafone