Rude call center agent

I called in because I had received a credit note from Flysafair and thought that same can be used as a voucher, I spoke to Trudy who tried to do the booking, the whole time she was shouting and claimed that my line was breaking. We then got to the credit note and I was trying to explain to her that what I was using was not a voucher but rather a credit note, after arguing with me about how the voucher should have 6 alphanumeric digits, and trying to explain to her that I am NOT talking about a voucher, she went to ask and then explained it back to me with an attitude that the amount was paid into my account and the note was just notification. <br> Clearly she is expecting that we know what the rule with regards to credit notes is at FlySafair even though she herself as an employee of FlySafair had no clue what a credit note is and insisted I give her a voucher number. She proceeded to put the phone in my ear without asking about the booking that we were busy with or checking if there was anything else I need or a goodbye. I called her back to speak to her supervisor which conveniently had stepped out. She is rude and has no idea what customer service is.