FNB REFUSE to pay back my MONEY on DEVICE PLEDGE

I am in utter disgust and very displeased with FNB. I took their phone in 2016, and it got lost. When I told them of the phone being lost they told me it was never insured. They however said they will continue billing me, and I allowed such, even without me receiving their minutes and data monthly. Now I settled my account of the device for R600, which they charged me R1 as a penalty for settling my account. Mind you, these people have R1500 as a security amount they are holding on this account. Now that I want it, they keep making promises that they will pay my money. Before I can speak to anyone, I have to hold for over 10min. I am really disappointed about the level of service at FNB and the greedy for the money they have from their customers.