3mobile dongle

Any help appreciated. All was working fine but now when I click to connect it comes up with an error message saying connection attempt has failed. Any ideas it has happened twice before but they just keep rebuilding laptop and charging a bomb.

is your credit ok?
what happens if you try in another location?
what happens if you try on another PC?
which version of Windows?

I would steer well clear of any outfit that sees the first answer to a computer problem as resetting machine to its factory state. That should be the last resort and if it didn't work for long the first time round then it's very very unlikely to work at the second or third attempt.

I'll add to Jon's questions: is your computer an older machine with a built-in dial-up modem?