Th reason is fine but how if the real owner lose their phone number accidentally? Since there is email verification, 2FA and even KYC verification, there should be a way to change the phone number by proving that the one who request to change the phone number is the real account. It reminds me that my registered phone number in Fortunejack is not active anymore since few years ago, fortunately phone number verification is something that is not being used regularly there is no significant problem related to phone number.
This is the next step to not paying.
I wont say that far, it is about phone number only which is not being used for any payment (at least till now). Even if it will be used to verify withdrawal and players has no access to the number, I'm sure Fortunejack will give an alternative way to verify as long as players can prove the ownership of the account.