Short Term Lease and Utility Bills

My question involves landlord-tenant law in the State of: New York

I rented an apartment informally (no written agreement) recently for a short period , 2.5 months and the landlord and i agreed on a fee of $1850 / month + $50/month towards utilities. The A/C unit was not properly installed in the apartment (the landlord had promised to have this fixed) and there were no curtains to create shade (or for privacy for that matter). This it seems has resulted in a higher than expected utility bill. The landlord has threatened to sue me for the difference (approximately 400 usd).

Does the landlord have a case?

Other points of note with respect to the sublet:
1. The landlord had entered the property once while drunk without invitation
2. The landlord warned my not to inform the super of our arrangement because apparently it is not permitted in the building which obviously made things somewhat uncomfortable.

I cannot read your lease from here, but if your lease says that all you have to pay is $1,850 per month and $50 toward utilities then that's what the agreement was.

Thanks for the reply : In this case there was only a verbal agreement for a lease reflected in some email conversations.