Over charging and ammending rates ********ly. ***

I have an issue with the statement invoice i went online 27/03/2020and generated my statement and the amount I OWED on the statement was R447,62. So I paid the money immediately I paid before the 30 th ?

Then today I generated the statement for April and it state that o owe 507,62 stating that :less incoming payment but I paid all the money on the statement this is totally absurd what is the 60 rand for because I paid before the 30 th of MARCH