Query regarding HDFC CC EMI cancellation

Yes they will calculate interest from your last billing date on a pro-rata basis. Moreover, u will have to pay full amount on next day only of emi closure

You can check all charges and fee and cancel online from mycards.hdfcbank.com > linked EMIs

Do update us about the charges and issues faced by you. 

hdfc emi cancellation is never transparent , last times i saw processing fee + emi_intrst charges 

this time it reversed me processing fee but charged me 25rs as Emi_intrst 

moreover when i  pre closed from my cards  it shows different amount but when i  paid and checked after 3-4 days it was showing negative amount (i.e i paid extra amount to them,  same thing happened this time as well)

HDFC also gives reward points for balance amount

HDFC can't reverse the emi processing fee if u cancel the complete order/transaction...that shows how worst they're.

I have filled the form to close EMI from mycards website and entered otp. Will the bank customer care contact me or I need to ring customer care ?

on receiving the email or regularly checking mycards.hdfc by logging in, you should place request for cancellation as soon as the transaction is converted into EMI and the processing fees and it's corresponding GST are reflecting there. you should do before to the upcoming bill generation to get entire charges reversed except GST else you will loose one month interest and processing fee.