Deceased Estate. FNB not answering phone

My husband passed away 3 years ago. He had a FNB credit card. I am unsure of the balance. FNB have lodged a claim against the estate. Which is fine. What is not fine, is that they do not answer the phone or reply to emails from my lawyer. I decided to try for myself. The phone rang for 40 minutes without anyone picking up or even a voice recording telling me where I was in the queue. Eventually I gave up! All we want is the find out the balance so that it can be paid and the estate can finally be wound up and I can plan the way forward. I would appreciate it if someone would contact me to finalise this