There's your problem. The UA MP numbers are three letters + five numbers. Is your third letter a capital O and you thought it was a zero?
My family, with 6 MP accounts, are all two letters plus 6 numbers.
2 of the accounts were opened prior to the merger under CO (that got merged with our old MP numbers).
The remaining 4 were opened in the past 4 years. The last was created about 18months ago.
All of them are US based account.