• Payment pending from employer

I joined company in pune and worked their for almost 10 months ,however even after repeatative demand for appointment letter ,employer didn't provided however they provided per month salary on 10th of every month in cash.

Now If i want to show the experience how I can show as I do not have neither appointment letter nor experience letter from employer?
how to file complaint against employer ?
What further steps can be taken ?
pls advice.