help for a hacked account

My ATT Yahoo account has to have been hacked as it would not allow me to log into the account on my computer online, but was available to me on my other devices. I tried to change my password on att.com, but once I did that and tried to use the new password, it would automatically send me back to att.com to reset the password. It did this about 5 times, now won't allow me into the account at all on any device. Because of the COVID-19 I cannot get anyone on the phone to help me with this and my email has been totally hijacked. Can someone help me with information about how to get it back.