How can i minimise my data useage and my airtime useage

Turn data off in settings

capitec has simplified their operations to provide clients with online transaction in so many ways. One of such is if you want to buy airtime, data and SMS bundles or electricity, do it the easy way with capitec cellphone banking. Just sign in and buy what you need to stay connected.
Details here - https://lailasnews.com/how-to-buy-airtime-with-capitec-cellphone-1203279-capitec-bank/

Only turn on the data connection when you need to use it

This is a rhetorical question. You have spent long time on internet until your R4 50MB became exhausted and your airtime was programmatically been used on the internet. Please make sure that u buy more MB than airtime to avoid this situation.

Data is different from airtime. Each has their own plan.

talk to your cell provider an tell them you want to cancel your account

"Airtime" will be billed on your account as used, once your 75 minutes included with the contact are used.
SMS and Data can be topped up at anytime by purchasing a Bundle.
Either purchase at a till point, via your online banking or by dialing *111#

To send photos you need to have MMS (Multimedia Messaging Service) activated on your phone and airtime contract. If you want to send the photo via email then you need to have a data service active on your contract and on your handset.

Check with your network provider: if MMS is included in your airtime contract then they will send the correct settings to your phone. They can also tell you whether you have a data service included and also send the correct settings for that service to your handset.

Your phone is very basic and lacks BlueTooth, so if you just want to send photos to a printer or to a nearby friend's phone, you cannot use that method.

I need airtime to call my sister for happy birth day she's turning 30