When waiting long enough in a queue we suggest customer to create callback on a number they call from or another, when entering another number mostly everyone would expect that it will be a local number, but there can be cases where customers are having international number. How to differentiate these calls, while keeping the logic that customers could enter just a number (via dial pad) without a prefix and we would expect local prefix to be added.
Example (local 1):
Customer calls Germany Support -> enters callback number "123 4567890" -> System adds "+49" prefix (+491234567890 - Germany)
Example (local 2):
Customer calls Germany Support -> enters callback number "49 123 4567890" -> System adds "+" prefix (+491234567890 - Germany)
Example (international):
Customer calls Germany Support -> enters callback number "371 123 45678" -> System adds "+371" prefix (+37112345678 - Latvia)
Assume the calls that are international could be from various countries
Maybe anyone could share expertise on conditions how that could be potentially achieved?