Data disappear at alarming rate

I have pre-paid Cel C ON SEL number ********** 889 They (Cel C) have a dat plan for R12 and offer unlimited access to sending photos and videos for a whole month via whattsapp, whih I loaded and a R49 200MB data plan which I also loaded, but in this month I have loaded addittional R140 plus and I can't send whattsapp, n 12 Oct I loaded R100 from wch the R49 was deducted leaving exra R50 + n my accounton 19 Okt I could not send whattsapps (remember Iam supposedto be able to do it fo the whole month, so I bought another R100 and on 23 Okt , 4 days later , again I could not use whattsapp and after 18h00 I loaded R40 and the very next day I cant use whattsapp at R40 per day makes R1200 per month additional (additional!!!!!!!!!!!!!!!!!!!) I cant use my whattsapp and that ius customer service, I am nt allwed to swear so I ANT EXPRESS MY ANGER AND DISAPPOINTMENT