Data Shock

I have a cellphone contract with Telkom & every month on the 1st they load me with 500MB of data & the data roughly lasts me about 2 weeks & I know I have to top up, which I never have a problem doing so I called on Saturday morning at 3am & I got a hold of someone who assisted me & she loaded me with 500MB, at 10am my data rand out which I did not understand why because I haven't downloaded or even updated anything let alone watched any sort of video and I decided to call the call centre and spoke to Sinethemba who told me all the activities I did but still it did not add up, she agreed with me & gave me a Ref no.s & told me I would be contacted in 2days & same day I loaded 250MB as advised by one of the agents just to see if there is a problem & that one lasted me 15 mins. Monday I waited for them & during the day on Monday I contacted them & I was told the technical team is not in I must wait until they resolve the matter because my case has not yet been touched, today I went to one of the branches in Sour street, I have never seen such slow service like that in my life, so I left without any assistance & as a customer who pays monthly with no fault I am appalled!