I had to format my thumb drive after I've tested a software which is used to test the thumb drives are good or not.
I tried recover my files with various softwares to get my data back.
I got them but all of my files are damaged.
I saved my important excel files in it.
I'd like to get my excel files back.
Please suggest me how to do and share me some software to solve my problem.
I'll be waiting for your suggestions.

Reformatting a drive wipes out the file system which will damage the files. If they are overwritten they are unrecoverable so I wouldn't anything else to the drive. There is software that might recover some of files but it is $$$. You could also send it of to a specialist but again that is also $$$. You need to ask yourself if it is worth it. Google.

I don't understand why you had to reformat it.