over billing and promised to be taken to legals

im Robert the problem started 4 to 5 moth ago.when realizing that my 2 gig top up contract is not showing the megabytes i have i call voda and they told me that the technician is buzzy with the problem.i call them several times and told to take the sim from the stick and put into the phone to check all the time. when doing that i exdentaly put the vodacom open line in the stick and use it. the bill come out as around R7 000.00 i report the mater they promise to deal with the problem. is then that somebody phone me yesterday and told me that i must pay the money or being ejected from the network and they will send me to the legals. i told them their problem but he insist on that and promised to give me a discount on that. i told him that i don\t have that kind of money and shows no sympathy. i told him that if it is not the problem of their technician 'it will not have happened. i also asked him to take my mater hinger and he just insist on that. i really dont know where i can get that kind of money and i don't want to be ejected from the network as i have three line in the network. pleas help me. "