Account opening and demat amc

I have opened new account on Feb 2018 and paid 300₹. I thought this amount was for 1year demat AMC charge. Last week I got charged 118₹ towards demat AMC. So I paid this 300₹ just for 2 months?

The Rs 300 you paid when you opened an account was the account opening fee. AMC is charged on a pro-rata basis at the end of the financial year. More here.

Okay. But still 100+ GST (118₹) for 2 months is not pro-rata (considering 300+18 for 1 year). Also since my portfolio size is less than 2lac, my account should be BSDA and pro rata should be on that 100₹ amount.

You can create a ticket here https://support.zerodha.com for your query about the AMC charge.

Unless specified your account won’t be opened as a BSDA account. However, if your account is eligible it will automatically be converted to a BSDA account at the end of the current financial year.

if the demat account and the trading account of the client is having NIL balance and dormant for the last 3 ~5 years . The broker , thus , has stopped debiting the AMC charges . Now , if the client reactivates the account ; will the broker debit and charge the AMC for all the past 3~5 years ? will the broker also charge the interest ?