Unfair request by the landlord to pay a fine for bounced cheque

Dear Mr Naser,

My cheque returned due to insufficient funds.

I received a text from my bank regarding bounced cheque and deposited funds to cover the amount and tried to reach my landlord, offered her cash delivery in an hour or bank transfer not to cause any inconvenience due to any delayed payment. She refused it.

Next day, I received an email from her that she has proof from my bank that it bounced back due to insufficient funds (which is true) and wants to meet me with her lawyer and asks for AED 5,000 penalty. There's a clause added on my contract;

"IN CASE OF ANY CHEQUE BOUNCE FOR ANY REASON, THE PENALTY WILL BE AED 5,000 PER CHEQUE & TENANCY CONTRACT WILL BE TERMINATED & SECURITY DEPOSIT WILL BE NON-REFUNDABLE".

Is the added clause legal? Isn't it too harsh?

I tried to find it on RERA or RDC but wasn't able to find info. I tried hard to pay them on the same day but they didn't accept. Looks like they are trying to benefit from the situation and making another AED 5k.

Can you help me?