Please look into the call center service

The service that I received in the beginning was excellent, but after many requests on email as well as when they phone me that I prefer correspondence through email I still receive more than 5 phone calls every single day from there call Centre. I also told them on more than once that they must not phone me since I am not able to confirm any information over the phone, and that if they phone me on the 25th asking for payment.......how do you pay when your salary is the last day of every month. I do appreciate what they are doing and I do believe in the work they do, it is just there after service is lacking, it feels as if my requests are not noted.