What happens if my funds remains blocked after IPO allotment?

If you didn't receive the allotment and the funds remain blocked, you may reach out to the bank of the UPI app you use.

Note that every UPI IPO mandate request has validity date which you choose at the time of accepting the request. In case the funds are not unblocked after allotment, the funds get unblocked automatically when the validity expires. Usually banks keep 12 days validity.