I have been working on CPT from April 2015, They applied my H1B which got approved. I was expecting my status will be changed to H1B from October 1 and also Medicare and SSN tax will be deducted from paychecks. But after October, my company didn't deduct any amount for those taxes, so I made a call to my company's customer care, they told me that my H1B was applied as consular notification that's why My Change of Status will happen only after I got stumped so technically I was still on F1 status. I traveled back to my country in November and also got stamped.
Now my company asked me to pay SSN and Medicare tax from October as on I797 approval date was mentioned as October 1. But as my change of status happened only after I got stamped that is in November, shouldn't I pay tax from November only rather than October?