Hey,

Incase you didn't receive any OTP on your mobile, please check your mail. You may have a mail regarding your registration number there.

If you find your registration number in the mail, then visit the official website and you will find the option of 'forgot password' there. Click on that and proceed as per the instructions.

If you don't have any email, then you can also visit any office of SSC CHSL near you. They might help you. Also, you can visit their official website and you will find contact number or mail id of various officers there. You can contact them.

Hope this helps!