MISSING DATA!!!

I have a contract phone and I purchased extra data . Each time I purchase data I also get a night surfer which kicks in at 00:00 mid night till 07:00am. To my surprise when I used the internet at 03:08am ,I received an sms that my data has been used up and I am now accessing the internet on the out of bundle rate. I contacted the call center and spoke to Sanelisiwe Ndlovu who was of assistance and I had to repeat my case more than twice. She advised it was because I did not restart my phone. I have never had to restart my phone when using night surfer, why is this happening now? I told her that I want my case escalated to her like manager and I needed an email sent to me with her details and line manager. I requested the call recording as she said calls are recorded for quality and security purposes. I WILL NOT BE BILLED FOR DATA I DID NOT USE!!!