Unprofessional behavior

I am a policy payer for my partners greenlight policy and the premium has been increasing tremendously and my partner and I took a decision to ask old mutual to reduce the premium which will result in reduction of the benefits Old mutual said we need to write a letter in that regard A letter was written and sent to old mutual but the premium was never reduced I called old mutual today and spoke to Chantelle at customer service and she wanted a reference number for the letter and I told her that we never received the reference letter and I said to her can I resend the letter and she dropped the phone after I had asked her to be on the line while I send the letter she said she has other customers and I don't understand why she did this because I am also a customer