Call center agents Very Rude and all have different stories when trying to get answers

I got a rain router plus data and minutes sim cards last year July 2023 in which the person I spoke explained to me that Im on pay as you use service agreement in which I will get internet when I pay and will be stopped when I dont in which I wont have to worry about monthly deductions. She calculated how much I will pay as it was during the month and that on the next month ill have to pay a set amount of R559. Now in November I delayed paying to see if indeed they would cut off the internet in which they did and it came back after i had paid. December me and my partner left the country on the 16th in which there was no internet connection on to come back in January and be told I owe December, CLEARED that with the agent and somehow i was credited. On February the app showed I needed to pay R49.91 in which I paid and after a few days they cut off the internet, March I paid the R559 and April 4th but now they cut the internet again saying I owe them again R559 which makes no sense as to why as they cut off the internet