Fnb pathetic service

I had a fnb home loan there was issues with payment and fnb gave my ex husband and I an option for the flat to be sold I signed the offer my ex husband however refused. Fnb was not getting their money from him and they gave us the option to sell as a last resort but still they did nothing when he refused to sign. I am now listed as a bad payer and have all kinds of things on itc because of this. This was a joint loan of the loan was in arreas why were we even given an option to not sell The service I received from FNB for years as this has been going on for years is PATHETIC! I was then constantly contacted to make arrangements as I am now alone liable to be paying arreas on a homeloan that I signed to sell. I have been paying for a year now then when I ask what is happening why does my ex not pay they tell me they cant get hold of him... really. So he refused to sign and now I am paying arreas for both of us. His details have not changed why is FNB doing nothing to him but holding me accountable for his choices