I guess there's no further date in JIPMER's schedule which permits one to alter their details.
All you can do is send a mail to the office stating your issue at the earliest and if possible, try to call the JIPMER office in Puducherry. Although it's quite certain you won't be receiving any positive replies.
As of now, I can tell you that the mistake in phone number will in no possible way bar you from giving the exam. It would hardly create any problems for you.
Don't worry, just prepare accordingly and give your best.
Hope this helps.
All the Best !
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