Home Credit India - Levying heavy interest without prior intimation

I had purchased personal loan from home credit India i n Oct **** for ****** @**% interest/pa for ** months term at emi Rs ****/pm. I paid emis till march on time and opted moratorium for * months (April** to Aug**, ******=*****). Now as per their records, I am liable for Rs ****** principal amount, (***** is interest for moratorium period of * months) @**% for ** months term without having any intimation to me while restructured. it means I have to pay approximately Rs ****** in total for just Rs ****** of principal amount. For the first time, I asked them through mail regarding the details, they said you have to pay this amount since you opted for moratorium. I sent many mails that I would give complaint, now they say it is because of technical issue.