Hi there,

Hope you are fine. First of all you do not need to worry.  Your answer sheet will not be rejected. If you have filled double bubble for roll no. in omr sheet.

As if you have filled wrong bubble in omr sheet but wrote right roll number in sheet in form of digit then software will check your roll number with other given data and your result will be declared accordingly. So, don't worry. Everything will be fine.

Hope it helps you

Good luck!