Smart switch just deleted my old phone data

[TAMATAMA]

Just brought new samsung phone, in a process to transfer my data to my new phone with smart switch 

suddenly it restart and factory reset my old phone, anyway to revert this ?

[TAMATAMA]

and no i dont have any backup whatsoever, that phone is my backup

[Fiona26]

Unfortunately if you did not back up any data and the old device has been factory reset, then there is no way to revert. Although if you did use auto back up with Google or samsung cloud one drive, do check if there is any data available at all.