Flipkart — Flipkart account is operated by someone else

Hello Team, I lost my number associated with flipkart few years ago. Since then I have not been using the account linked to my email id: [protected]@gmail.com. Since last 2 years someone is using my account with my previous number. I can get all the updates for this account but unfortunately I cannot deactivate this account, for deactivating it send OTP to my old number. I cannot even change the number because it sends OTP to the old number and the new number. This is such weak security from your side. Can we not deactivate the account with the old phone number? Is there no other way?