staff not knowing what they do

i was told that I have to make a 10% payment on my account, which added up to being 2200. I then arranged that I will pay 500 each month until the account is settled. last week I received a sms to say I must pay 2200 again. I phoned them and I was told that the person whom I spoke to is not authorised to make payment arrangements with clients. when I requested a copy of the phone call so that I can take it to my own lawyer nobody was able to assist me. the very quickly remind you when you phone the call is recorded but when asking for it , they don't seem to have it. why was the person I spoke to not informed that she is not allowed to make payment arrangements? why didn't she tell me (if she knew) that I have to talk to someone else? i was told that if I want a copy of the phone call which is still missing) I have to send an email, I am still waiting for a reply on the email, I had to phone again and i was told again that it will be given to a supervisor. very very unprofessional company.