I was tracking the "join to our group" forum topic, but even now that it has been  (providentialy) removed, i keep receiveng alert messages for 5 new posts in that topic.

Does anyone know how to solve this kind of problem? 

You can go to your profile ("My Home"), click on My Account in the upper right, and there is a link to manage your alerts. You can uncheck any alerts you don't want to receive there.

I've already tried that, the problem being you can only choose whether to receive alerts for new comments or not to receive them at all. 

I'd need to stop tracking  just that one topic, but I can't do it as normally simply because the topic is no more available!

hmm. good question! can't you just click on the IGNORE button in your alerts panel? let me know if that doesn't work...

Ok, I also tried that with the result that this time I'm not receiving alert messages anymore, but in my profile's window, under "new comments" it's still notified "join to our group" "5 new comments"!

 

ok. we will get this fixed :)

thank you very much for your attenction!