Guys , having a problem with end-of-call-report webhook , in UI it's saved as hook that i want , but if i send GET with HTTP it shows me that my old one is still beign used -_-. How can i change it ?

Vapi may still use your old webhook due to server URL priority (function > assistant > phone number > account) to fix it update the URL at all levels especially in phone number and assistant settings and remove any overrides in assistant functions..