Nestaway Technologies — Property management

I had a property management agreement with RealtyCart for my apartment in Bangalore back in 2014. RealtyCart changed to Zenify and Zenify sold business to nestaway at some point. I stopped receiving rent from August 2019, and finally received note from Nestaway that tenant moved out in Nov 2019. I was not handed over the keys, i had to get the duplicate keys and upon entering flat i found it to be completely broken condition. I contacted few repair companies and got quote of around ~1.23 lakh. As there was no one from Nestaway available to take care of that, i finally hired local guy and spent around ~50K to bring flat back in livable condition last year.
This year i have started receiving emails from nestaway for settlement, asking me to refund security deposit, legal threats.
Please help resolve,