For a business location verification I never get a card from Google !
In any case , i do not have a Box Mail to the 2 nd business location so in impossibility to verify the address by mail !!
Why is not possible to verify a business location simply by email or the phone number ?
If you have been waiting more then 14 days for a postcard then I recommend getting in touch with GMB support via one of these options to ask for help in getting verified: