how to change 4g sim

How to receive 10GB of free data when changing SIM 4G Viettel
starting from march 8, 2017, when sim viettel converted to sim 4g will be able to receive an additional 10gb of free storage when registering the program, and experience high-speed internet access.
How to check the phone is not deducted by the network?
the situation of subscriber's phone subscription is deducted unreasonably from mobifone, viettel, vinaphone network because you are using services that you do not know.