Do app permissions can cause trouble as some apps may secretly access your memory card or contact data?

It is not possible to "hack" a mobile phone without some form of software or exploit. The term "software" in this context refers to malicious code, scripts, or apps that are used to compromise a device. All hacking methods rely on some type of code to achieve a result. Furthermore, unauthorized access to a mobile phone is illegal and carries serious penalties. 

Yes, a voice password is theft-proof. The voice authentication system is smart and only gives the required permissions to the owner. It is safe and secure and won’t take command if the sound of the voice is distorted or an arbitrator tries to mimic the original user, etc.

It is known as Vishing Call. A vishing call is a fraudulent phone call where the caller poses as a representative of a legitimate organization, such as a bank, in an attempt to obtain sensitive information from the victim. Banks will never request personal information such as account numbers, social security numbers, names, addresses, or passwords through email or text messages.

They will only request this information for identity verification purposes when you contact them directly. It is important to remember when receiving unexpected calls to avoid providing personal information over the phone. If you have doubts about the authenticity of a call, it is best to end the call and contact the bank directly using the phone number provided on the back of your card or on their official website.