Cognizant interview questions

I applied for AI Engineer on senior level and got selected after clearing 3 interviews but they did not want to offer me rightful salary that was standard for my experience and skills and flagged me not qualified due in the document verification stage. Lame reply was : Failed in background check

I have placed in Cognizant on dec via on campus 4 lpa. 1)communication round 2) aptitude 3) coding round 2 sql 2 coding 1 (html CSS js ) ques 4) interview ( technical)