Funds taken out of my savings pockets without cons

FNB Home loans service is appalling. I have had my account double debited just this month. Have been calling their offices, they say it has been rectified and nothing happens. 2 months ago I had funds taken out of my FNB savings pocket by FNB home loans, which in my view is a breach of any legal contract as there was no agreement in this regard. I am extremely frustrated at how FNB treats its loyal customers as I have been with them since 1994 and have never been happy with their service. I have dealings with other banks and have ever experience such. Definitely moving all my business to where I can be valued as a customer !