What are the consequences for one who entered into a state of Ihram for 'Umrah as a Mutamatti', then did not enter into Ihram for Hajj due to severe crowding and departed?

If you have performed Hajj al-Islam, then there is nothing upon you. However, if you have not performed Hajj, then the obligation was to remain to fulfill the duty, and you must hasten to perform Hajj whenever you are able. As for the mutamatti‘ (one performing umrah (definition) followed by Hajj), if he entered ihram (definition) for umrah and completed it, then decided not to perform Hajj before entering ihram for Hajj, there is nothing upon him, unless he vowed to perform Hajj this year, in which case he must fulfill his vow. But without a vow, there is no blame upon him for not performing Hajj after umrah.