All right! Take it easy!
In these days, it is not difficult to recover lost data from Galaxy grand phone, provided that you've not overwritten it with anything else.
Anything new on this phone may overwrite your lost data and make it gone permanently. So, take care.
And then, in order to recover your lost data back, you need data recovery software that is professionally developed to help user retrieve inaccessible data from a phone memory card or computer drive.