Punished for being long term customer

Hi

Over the past 3 months my monthly fees are fluctuating, and I don't understand why? It was 896 then 902 and 960 and I'm getting frustrated. I am already being punished for being a long-time customer by paying far more than your new customers

I need to understand why my charges are fluctuating and preferably in writing ***×******************* Sent this email on the 1st of February and no response to date