Paused ad campaign continued to run

I set up my first ad campaign a few weeks ago and was disappointed with the results.
Last week I paused the campaign to have a think about whether I would continue at some future date.
At this point the charges were about £20.

Today I have been billed £50 and checked to see what was happening, the campaign was still running.
I paused it again and then, about half an hour later went back to see that the campaign was running again. I have now archived it, so I hope that’s the end of it

What am I doing wrong? Is there something I have missed?

Many thanks

You ticked the box, went to the top pull down menu and pulled down to ‘pause’?
Usually works.