Maybe this is old news too you folks -
https://www.theguardian.com/money/2020/feb/08/bank-couple-lose-43000-but-cant-get-a-refund
but regardless of whether you sympathise or not with the (un)lucky victims - 'scammers were able to keep the line open during this process, using fake dialling tones, phones ringing in series, and even phone transfers'.