Ok, I think I understand now, but just to check, we are talking about 25 Giga-Bytes?, which would be a bill of thousands of rands at R2.00/MB on Family Topup, which AFAIK is a pre-paid product...
The only scenarios I can think of that would make this possible, are
- if your brother's connection never dropped once while he was downloading that 25GB; or
- your brother had several thousand rands worth of pre-paid credit on his Family Topup pre-paid account; or
- somehow your brother's Family Topup pre-paid was in reality a post-paid contract - maybe the retail outlet screwed up when activating the Family Topup account; or
- your brother didn't think he was using the VLive APN, but actually was; or
- your brother was dowloading from a bandwidth twilight zone

How much did he endup being billed for the 25GB?