i did hang up and so did my bank
If the call was to a bank then would they not record all calls for quality and/or training purposes as many large businesses do?
I wonder if they could provide some evidence proving the time and duration of the call?
I'm not actually sure if that's at all possible, but just an idea.
@malcolmx , @AllyM could well be correct you might well be able to make a Subject Access Request under the provisions of the GDPR. Such requests are free. An example of how to do this, for NatWest, can be found here. Under the Write In section it states:
Thus implying that calls and the related data are available.
Of course the process will be different for each bank, but it might well be worth contacting your bank and seeking their help with regard to the call details.