I am working on a social networking community website. It keeps getting fake user registrations spamming the system by forcing the site to send out confirmation emails to the email address and usernames they provided during the signup process. I don't think these user's ever wanted to create an account at all because of their supplied usernames. Those username are as such that they all end with a long sting of numbers.

Some examples obvious spam usernames are:

jonsmith088723682
sallyjane31067495
markjensen99409291

Likewise, they will use similar spam emails which are almost certainly fakes.

Some examples of obvious spam user emails are:

jonsmith088723682 AT  Philippines.travel.network 
merryclause365510394 AT  clothes.shopping.club

The major problem that I'm having is the WordPress plugins I'm using (and I've have tried a number of them) are not stopping these clearly fake registrations. I don't approve new members automatically However, I don't want my site sending out these obvious fake/spam usernames and emails. I believe they are trying to tarnish the brand of my website by making it send spam like messages from my site across the networks (due to data they provided) to non existent emails accounts.

So how do I use Cognos Analytics and in conjunction with what other products would be needed to solve this problem?

Thank you all very much for your help!