They give out Misleading Information

im on an open line with Cell C (no: ***) which means if I use my monthly bundles and finish them what ever i use will be charged out of bundle. I called them to get advise as to how i can save and not end up paying a large amount and was told i can put on alimit which will mean that if go out of bundle and use that limit then my phone line will be capped and will not be able to use any further but will pnly recieve calls. I put on a R200 limit, so it would mean its my montly subscription plus the over limit amount. I have since been paying just over R600 and have never even once was my line disconnected because i used over my limit. I called Cell C today 09/07/2015 to confirm this and was not able to to get clarity as to why has it not ever been disconnected since they had said if you reach your set limit when your bundles have been used up then your line will be capped. I fail to understand why they put something in place and it doesnt work