I feel your pain.
I have just checked the speed to my laptop. Despite paying BT £50 per month for Infinity my speed tonight is 0.36 mbps.
Now I know if I connect my laptop via an ethernet cable to the modem it will increase significantly. Was this explained to me on sign up? No.. what's more BT's get out clause is a post script in small font at the bottom of your welcome email.
I would say at this point: In this day and age who the heck connects any laptop via an ethernet cable?
BT Customer Service is a joke, and a somewhat ironic name for a department that simply ignores complaints and refers you to tech.
What do Tech say? Try and get out of your contract. Here's the number...
Meanwhile I have a service that is patently not fit for purpose.
"No ISP guarantees wireless speeds there is to many potential external interference sources"
Hardly helpful since the speed to my laptop last night was 0.36mbps. My next door neighbour whose ISP is EE gets a regular speed of 40mbps on a wireless connection.
It can be done but apparently not by BT. Current advertisements are at best misleading.
NONE of this was explained to me on sign up.