Fixed Interest Rate

On the 24-03-2016 a lady from Standard bank called me in regards to the home loan Interest Rate that I wanted it to be fixed, she called in the morning then I requested that she phones afternoon since I wanted to think clear about the fixed rate that she was offering to me. She called back at 15:49 and I accepted the rate of 13% and I mentioned that it should start from the 25-04-2016 all off a sudden I am getting smses from Std bank saying that my account is in arrears, on the 30-03-2016 Ntombi from Std bank called me and said that I must pay R500+ on my home loan since it is short. when ask why she mentioned the 13% interest rate, I therefore asked her to investigate it since to my knowledge it will start in April. 15:00 30-03-2016 received sms then I decided to call spoke to so many people, from Mapiletsa who gave me another number that I must call, and finally spoke to Millicent who said there's nothing she can do since I wanted to cancel this thing cos my account is now in arrears. Have send letter of complain to Std bank still nothing that means my bond is in arrears and I remember mentioning that i want this extra cash to start in April not March, and I can't even cancel