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Do you mean after resting your phone all the files were disappeared ? or after restoring you created some files and those files are missing ?
Do you have a backup of your files ?
That's great !! It seems like somehow those files are now hidden in your phone. Please check if auto sync is on in your iPhone
I am not sure about the price and the cost associated with this question. We do not have access to those information.
Alright . No problem. I will raise request to get your refund.