How to deal with late payment penalties of purchased property installments?

Dear Sirs,

Ramadan Mubarak to you.

I am writing to inquire about the following. I bought an apartment in Dubai in 2016. The handover was to be in 2020 but the project is still not completed.

I paid the first 5 installments but then I had a financial problem so I could not pay in 2018 and 2019 installments totaling AED 140,000.

Finally, I just paid it and now got up to date, however, they have now sent me a bill for AED 700,000 late payment fees. The property itself is valued at 1.2M.

What can be done about this? I am getting ill from the stress.

Thank you