No matter how careful you are, the service(bank, SNS and everything) you're using aren't. If you hand over them a phone number and they think phone number alone

No matter how careful you are, the service(bank, SNS and everything) you're using aren't. If you hand over them a phone number and they think phone number alone can identity you, you're done for. The only solution is not using the phone. The phone reached it's limit. It's not trustworthy communication method.