If the account was hacked/compromised and unauthorized calls and messages were triggered from the account. We recommend the following actions immediately to avoid any further misuse of your account, please follow the same sequence - change login password, change auth token and enable 2FA for the main account and all sub-accounts (if you have any).
Please follow the below links to complete the actions:
1.Change Login Password: https://console.plivo.com/accounts/password/reset/
2.Change Auth Token: https://console.plivo.com/account/auth-token/generate/
3.Enable 2FA: https://console.plivo.com/user/profile/
If you have additional queries please create a support ticket.