Employment related

Dear members

I had joined a reputed CA firm in my City. worked there for 15 days and then for some genuine reasons i had to resign as one of my family members was serious and i had to shift to my hometown. i could not meet him to tell this and informed on phone. i have no official appointment letter or other written documentation related to employment.

I called up and asked for 15 days payment, he says i have to pay one month notice pay or else he will inform icai as his work has suffered a lot. i have an argument that we have no written terms of employment and this was a genuine reason which was unforeseen.

what action can i take if he gets down to such a level to complain icai?

what recourse do i have because i dont want to pay him.

please reply urgently