You have asked this question before and got lots of replies. You need to go back a page and see them.

Soosie. If under "Your options" you click "your news" you should see a link to your earlier question with the answers you got.

It's clear that we don't think its campanula you have a problem with, but, as you're obviously not happy with the previous responses, give us some more information please

Which campanula is it, precisely? What exactly have you tried to get rid of it (which weedkillers, when, any other efforts such as digging). Where is it growing? And/or provide a photograph.

It might be C. poscharskana though, which does go mad in my garden and seeds itself between the paving slabs. Gosh I need a rest after spelling that one!