i think, now your problem is HARDWARE, these phone, have alls ugual problem.
If do u loock good the SLOT USIM, do u want see not have 1 of the 3 PIN, dissolder, and for this not READ SIMs.
Change this SLOT, and do u loock alls work good.
I repair more SLOT USIM (p910) thath DISPLAY or other.
In these phone, have need inser sim, very delicate, because this point is simple damage.
(excuse for my ENGLISH, but i think do u understand)
BR
Maxpizza