Disappearance of airtime and data - what manner of magic is this

Yesterday morning, I bought R8 power hour and had R435 worth of airtime left. I made calls only to vodacom users, I had a busy day through out and didn't spend much time on the phone. Evening came I chatted a bit on whatsapp and went to bed at 20:34. I felt my phone on the charger with my data on as usual. Every month I get R800 worth of airtime and had bought 500mb cause I use two phones and use the other phone more than this one. Nonetheless I woke up this morning to remove my phone on the charger, I find an sms that came in at 21:35 stating that I have less than 199.0mb of data available. Then another notification saying I had been charged R2 per 1mb since 7am this morning. To my surprise I had not been browsing, I decided to check my balance and was shocked to discover that both my airtime and data was gone leaving me with R0.00. I honestly feel like vodacom doesn't feel good if 6 months goes by and I don't complain to them about anything. I always either lose airtime or data. Vodacom may I have my data and airtime back please. If you insist on doing this to me I will move to telkom I've learnt they have a package of R600 worth of airtime, free calls to any network and 500GB worth of data. I mean I can save myself R200 and I am sure my data and airtime won't disappear on me. Plus your talking points rewards are lame.