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.
I'm also sure they would, but can this issue arise at all? I mean, if you lose your phone, you can get the same number for a new SIM card. I don't know about
all countries, but in most places this works for for sure.
Yes it possible to get new sim card with the same number but some time the process is a bit complicated especially if the used number is not registered using our own personal information as it will be impossible to prove the ownership of the number. I just have no idea with the rule that it is not allowed to change phone number during 10 years.