Hello Afaan,
Welcome to the community!
Sorry to hear of your situation. I understand you have previously attempted to contact customer service. However, you should note that this forum is community-driven and not intended as a venue for customer services. If you would like assistance with your matter, you would need to re-contact customer service. Unfortunately, they do not offer customer services via email. In addition, they can also be contacted via Live Chat, Facebook, or Twitter. I understand you claim not to have received a response to your messages on those platforms. Have you verified you are contacting their proper handles. Those methods can be accessed via the contact page posted above.
In order to prevent unintended roaming charges, it is generally recommended to disable data and roaming data. However, you should note that disabling those settings does not prevent roaming for voice and messaging. In addition, some manufacturers might allow some data usage to occur despite those settings (see here). That's why it is also generally recommended to enable Airplane and/or Flight modes in order to prevent unintended roaming usage. You could then manually enable Wifi when required. Alternatively, people have also removed their Fido SIMs card entirely, However, enabling Airplane / Flight mode or removing the SIM card would also prevent your device from making and/or receiving calls or sending and/or receiving SMS using the local cellular networks.
It is generally not best practice to withhold paying your bills when disputing a bill. In doing so, you will likely incur late payment charges (see here). Further refusal to pay your bills may lead to your services being disconnected. In addition, unpaid cell phone bills may negatively affect your credit (see here).
Hope this helps 😀
Cheers
