It looks like Egypt isn't the only place where an unelected regime is using the courts to nullify election results it doesn't like. Back in February, Kuwait's Emir dissolved the National Assembly and called new elections after his government was undermined by corruption scandals. Those elections were handily won by the opposition, who have since held the (unelected) government to account much more than their predecessors. And so Kuwait’s Constitutional Court has nullified the elections and reinstated the previous Parliament, causing a constitutional crisis.
The good news is that not even those MPs who kept their seats think this is OK. Over half of them have already resigned, saying that they do not want to serve in a parliament rejected by the people. From the look of it, this renders the Assembly inquorate and unable to effectively function (quorum for passing laws is apparently 33 members out of 50). The obvious solution is new elections, which will likely produce a similar outcome to the previous ones - but there's no guarantee that the regime won't simply pull the same trick, rather than be subjected to proper Parliamentary scrutiny.