Developer increased maintenance charges without prior notification

I am a NRI with a plot of land on the outskirts of Mumbai. I haven’t paid maintenance charges on the property for 10 years. The developer did not notify me of the charges annually even though my telephone and email address haven’t changed in the last 15 years. I have followed up with them by email since 2013 for details on how much I owe, but got no response from them. In Jan'18 I visited India and went to their office and was given an invoice of Rs 1,80,000, being maintenance charges from 2006 to 2018. I have been given time until Aug’18 to pay the dues. I would like these charges to be waived considering that the developer failed to notify me of the charges on an annual basis and despite me following up with them since 2013. I am financially not in a position to make the payment by August. Also, the annual charge has increased from Rs 7k in 2008 to Rs 20k in 2018. Does the developer not have to notify us of the increases before implementation? Do I have a case to argue these points?