NAB customer service non-existant

Worst customer support ever experienced. Spend hundreds of dollars on telephone cost trying to get somebody to pick up the phone at the customer support call centre. Voice records tells me to use the NAB app, but the issue is I can't use my NAB app/ ID, which is the reason I have to use my phone to get assistance. Have spent 3 days calling them on and off, waiting 30 minutes at a time, and nobody takes your call. Phoning from overseas and it is extremely expensive. Dont know what to do to get some assistance. Extremely disappointed