BenQ M300 - Manual (Page 87)

Menus 73
My Number
This option allows you to save your SIM card number and name to your
SIM card's memory.
Press (Option) and select Add to enter your name and number.
When you are finished, press (Option) and then select Save to
save your data. If you wish to edit the current name and number, press
(Option) and select Edit to edit the currently selected data.
Memory Status
Shows you the entries that have been stored and the maximum entries
that can be stored, on the SIM and on the phone.