Cancel of gst number question

A Gst registered regular scheme pharmacy store business dealer business closed dt:31-07-22.if dealer cancel of gst number applied online in gst portal.dealer dt:2-08-22 notice received from gst department reason for query dealer itc excess claim previous years 18-19,19-20,21-21,21-22 years rs:5 lacs difference between gstr3b vs gstr2a tax amount show.
question:
dealer notice show amount tax pay compulsory
2.itc camparison provision applicable w.e.f.01-01-22 is correct