Night Express times not being honoured - MTN

Was told eariler and website states that nihht express is from 0.01am to 5.59am. I used up my anythimg data as i was on the neteork fat 5.20am. called mtn only to be told that it ends from 4.59am. I received no notification or even their websites currently say that it ends at 5.59am. To me ths is day light *******!