If you don't have another phone would it be safe to first call some other known number and see if that goes through?
If it does, then you should be able to infer that the previous inbound call has (probably [1]) hung up, and it is now safe to call your bank.
[1] A sophisticated enough scammer could hold the line, give a fake dial tone, detect that the number you are dialing is not the bank number they expected you to dial, dial that number themselves on a different line, and relay between that line and yours to convince you that you really did have a clear line, and then keep holding the line when you then hang up and try to call the bank.
https://security.stackexchange.com/questions/100268/does-han...