International assistance

I have been using my debit card and banking app in Thailand for almost 4 months now. 3 days ago FNB decides to lock my phone app and online banking. I got hold of them via email because it is useless trying to contact customer support. They did respond to my email and sent me a form that I had to complete and send back together with a copy of my passport and international contact number which I did straight away. I haven't heard from them ever since. Today I get an automated call from FNB on my international phone number to say that they suspect ***** on my debit card and that I need to contact FNB. I have waisted so much money trying to call them. They have my number, I don't understand why they cant just call me and speak to me. I am really not happy with the way they are handling this urgent matter.