Broadband cutting off since exchange upgrade

[#1]

In october I received the following e-mail from plusnet:
"We have good news for you. The exchange equipment we use to provide your service has
now been upgraded, and we can offer you a faster 'upto 20Mb' service.
You don't need to do anything, and we'll switch you over automatically, for free.
We expect this to happen within the next 5 weeks.
There may be a brief drop in connection for about 5 minutes on the day of the
change, and you may see varying speeds for the first few days after we've upgraded
you. This is expected, and is nothing to worry about. "
Since this upgrade has taken place my broadband cuts out regularly. Beofre that the connection was pretty much always spot on.
i cannot help but think that something has gone wrong in the exchange.
I'd be grateful if someone could look into it for me please.

[#2]

Or you have iffy internal wiring as the higher frequency is more affected by bad wiring 

[#3]

Have you tried connecting to the test socket to see if things improve?

[#4]

Hi riccardorob,
If you could test the connection with just the router plugged into the master socket (or even better the test socket, as sjrinfroyle says) with all other phone items unplugged from the line, then if the fault is still occuring please raise it to us via the troubleshooter at http://faults.plus.net