A few key points came up to me:
1) Throughout the entire tirade, the poster (Nison Chan) did not mention anything about the property management company not being compliant with the contract they signed, so I assume that's a tacit admission that they have no legal grounds for not paying rent.
2) Whatever the reasons the poster gave for not being able to commence operations, it's ridiculous to slam them with a "You still have the audacity to send us an invoice for rental despite out unit NOT BEING OCCUPIED and HORDED UP". Excuse me, you were unable to commence operations for your own reasons and now you are trying to frame the whole thing as a moral outrage because you yourself cannot start operations.
3) The reasoning that the poster should be treated differently from Shake Shack because they are "MNC" and he's only "SME" is a dishonest argument. There is no particular reason why the property management company should treat him differently just because he's "SME". If someone goes buy something in his shop and at the counter claims no money what would he do? Probably tell the buyer to either pay up or get lost just like everyone who paid in front or behind the queue. Would he accept if the buyer now claims it's "ridiculous" to compare a poor guy like him with other customers who are richer?
Assuming his description of his dealings with the Leasing Executive is true, this can at most be construed as poor customer service and/or a badly trained staff with a defective attitude. Maybe one can also fault the Leasing Manager for not being emphatic enough when delivering hard messages, but Nison's overall tone is very self-entitled and acted like the Company is obligated to help him due to business challenges he faced from COVID. The gist of it is "How dare you ask a SME like me to pay up when I already face business difficulties due to COVID?"