Why is a new bus company allowed on an existing route with same number, but higher prices?

COMPLETED: Read the report here

The 144 has operated between Worcester and Birmingham for longer than i have been around and has been taken over from Midland Red bus company by First bus company. A new company recently started between Bromsgrove and Birmingham with the number 64 and always had higher prices. That company now has new buses and renumbered to 144.

Because the number is the same, it is very confusing to the customers and feel they are being ripped off by having the same number. I have experienced it first hand at Birmingham Bullring with customers boarding and being asked to pay extra on their initial return ticket paid for from First bus company. No problem with having competition on bus routes, but claiming to be the "144" is a bit much!