Getting devices to speak to broadband

[#1]

hi, after long delays (over 6 weeks!)  my new phone and internet service with PlusNet went live on Wednesday. I had to set up a new account as my ex husband transferred the previous PlusNet account (it was in his name) to his new address, transferred it back to my address and then cancelled it. However none of the devices that previously connected into the wireless internet will now do so - two laptops, smart phone and kindle. We continually get an invitation to log into PlusNet, we do that, it says it has been successful and we can start surfing - but no, when we try the connection is timed out.
Any thoughts on what I need to do to get up and running? Both laptops say we are connected to the internet and the little bars show that we have a strong signal.

[#2]

Going on what you have said, I am assuming you are using your old router with your new account. I suspect the invitation to log into PlusNet is the wifi between your computer and the router, since this works it reaffirms my thought that you are using the same computer and the same router as before. Now I suspect then that your problem is your password for accessing your new PlusNet account. This will need to be set in your router. You will need to know what the password is then go to the routers admin pages and enter it. I don't know what your router is nor it's IP address so can't guide you on doing that I am afraid. Do you know what the admin password for the router is ? without this you'll not be able to change anything. It maybe be simpler to use the new router that PlusNet supplied (if they did) which will be set to known defaults and maybe even your account password.
To summarise
It sounds like your wifi is OK
It sounds like your router isn't logging onto the PlusNet servers
to fix it you will need
your PlusNet Account password - PlusNet will tell you this
the admin password for the router - might still be the default, might not.
the IP address of the router - might still be the default
the setup instructions for the router - PlusNet might have a guide for the router model

Of course I might be well off the mark so sorry if I am
EDIT: If you use a new router you'll need to set up your wireless again so you'll need your wireless password (or reconfigure your devices with the new password - not recommended). You will probably need to be able to connect using a cable until your wifi is set up properly.
Your router will probably have an reset button that will reset to factory defaults and the manual will give the default IP address and admin password. If you do this you will need to set up your wifi again and will need a cable connection to access the router until the wifi is set up.

[#3]

thanks for this. You are absolutely correct, same computer and same router. No new router applied. Don't know if I know my admin password etc or not - I'll have a look when I get home tonight. All I have is a sticky on the bottom of the router with assorted passwords etc on it. If it isn't on there, then I don't have it!