free email certificate

I got a free email certificate from comodo, then I downloaded it using the link sent to me.
I used safari and firefox, but both don’t install the certificate il the wallet.
I double clicked on the downloaded cert and the cert is now in the wallet but not as private cert.
No way to use this certificate?

nobody can help me?

I see in the forum they are other with same problem (i.e. https://forums.comodo.com/digital-certificates-encryption-and-digital-signing/cant-collect-certificate-t61137.0.html) but there is no visibility on solutions

it seems there is no way to login to http://support.comodo.com/ (for free users at least)

I posted an issue to support