Bad wifi

My parents currently have a Wifi package with 20GB, YouTube package and uncapped Whatsapp. It was sold to us like that and recently I went into the store because EVERY 11th the Wifi would no longer work. The call centre is unhelpful and when you ask for an itemized bill it does not describe much. I was told in the store that the whatsapp doesn't work anymore but it did before because the sim needs to be in a phone and the same with the YouTube, but we can watch YouTube when the package is "depleted". We have not been given a proper answer as to why EVERY 11th our Wifi is depleted and why the Whatsapp is no longer uncapped. We live in Hawston and I feel that this package was sold under false pretenses. We have school work we need to do and we cannot and I feel that they took advantage of an older couple that are not very "tech savvy"