it doesn't make sense to wait more as 30 days as every PIN will expire after 30 days.
Now you have to request a new PIN and wait.
If you have been waiting more then 14 days for a postcard then your best option would be contact business support
I recommend getting in touch with GMB support via one of these options and ask for help in getting verified:
Helmut Geissler, Google My Business Top Contributor | my G+ profile