With the T-Mobile Phonebook Backup service you don't have to worry about losing another important contact again as the T-Mobile phonebook backup service syncs your contacts, calendar and tasks with a dedicated, secure site so you can always reach the people that mean the most to you. More at tmobile iphone. This service is especially useful when your phone is lost, stolen or broken as you can visit this safe and sound site to view your important data.This incredible service allows T-Mobile users to securely backup all there important data to the T-Mobile network where it can all be accessed quickly and safely. Never lose a contact again with this free secure, 24-hour backup service available from anywhere in the world.This service allows you to update your contacts, calendar and tasks on your phone or online as one will always sync with the other so it's up to you which way you do it. This service is absolutely free to T-Mobile users who have a compatible mobile phone.The phonebook backup service also allows users to stay up to date and sync their mobile phone while out of the country abroad on holiday. The Phonebook Backup gives you free, secure backup for your mobile phone contacts so you can still get in touch with the people who are important to you if your phone is lost or stolen which means you'll never lose a contact.You can view or manage your contacts online or on your phone which gives you the freedom to always keep them up to date which also makes it easy to install them on a new phone. The Phonebook Backup service can store 2,000 contacts. If you have more than 2,000 contacts, you won't be able to sync or add new ones online.The Phonebook backup service makes backing up and downloading your contacts easy as it's all done using a process called synchronization. Once the synchronization is complete it will send a copy of your contact details and other phone information to the T-mobile network. For details, please click here.