Urgent!!! Account...monthly payments

Good day,

I want to know why i don't have a fixed monthly premium.

I have the following contracts: * Huawei cellphone * 1 Sim (068 *** ****)= 800mb * 1 Sim (065 *** ****) = 20Gig + 20Gig * 1 Sim (065 *** ****) = 20Gig + 20Gig (Router must be excluded for it has already been paid off in previous contract)

Monthly installments: * September 2022 = R366.47 * October 2022 = R383

All the contracts are on Top ups.

Please look into the matter and rectify

A. Champion