YashTel — Charges levied

I had taken a 6 month package last year, and not even used a single byte until April 2021. now when i try to recharge they say, i have to pay 700 Rs. Dont understand teh rationale behind it. if they wanted charge 100 Rs for non usage, keeping the account active, they shoudl have done thesame when i asked them to keep my account suspended in December. they did not do this, and now they ask me to pay. this is really cheating.