Speed

[#1]

I pay for upto 78mb download speed but only get about 21mb.
Is this normal?

[#2]

As a rule probably not but it will depend on your line itself. What were the estimates you were given when you signed up, or when you put your phone number in dslchecker.bt.com

Also, are you getting 21 via Ethernet or Wi-Fi? If wired is low there's likely a problem somewhere assuming that's not a result while the connection is in use doing other things. If Wi-Fi then it's likely to be an issue locally with the signal-interference or thick walls. Check the help guides on the site on how to sort these.

[#3]

Sorry to hear you're having issues with your speed.

Our tests are showing that your speeds are below the estimates for your line but it's not showing any obvious cause

I'd recommend raising a fault here so we can investigate further