Free.fr and wp_usermeta

Hi,

I’ve been looking here for the solution to my problem for 2 hours.
My problem is that i get this ‘wp_usermeta: Table ‘username.oneletter.wp_usermeta’ doesn’t exist’ while I’m trying to repair database.
Apparently there’s a bunch of french people facing the exact same problem with Free.fr BUT I still don’t get the solution.

Apparently it could come from the dot in my username.
Or it could come from my host.

Could you please give me instructions to repair it ?

Tanks for helping