Tbz — 10000 rupees monthly plan

I have taken a plan of 10k in Feb 2021.
I have paid my 1st instalment of 10k on February but later on they didn’t collect any amount in March, April and May.

They didn’t send any reminder either though sms or email.

Now they are asking me either continue the plan or they will deduct 500/- if I want a refund.

I called them and said there always no reminder and neither they picked my call, I could not pay.

They misbehaved and said that they have sent me a reminder.

I challenged them if they can show me the proof of reminder, I will continue the plan else they have to return my amount with interest.

Now they called me again and said that they called me but I didn’t picked the call but they did it send any reminder in written.