Confusing Experience

In last week I discovered an option that says I can purchase prepaid electricity on my account.

The option comes up on the website and my app. Tried using it, kept getting an error message.

Contacted Mr Price via WhatsApp and the agent says, oh it's cos you have to use Chrome on the actual website. I take out my laptop try it, same issue.

Her response OH THAT MEANS YOU CAN ONLY BUY IN STORE. My response WHY.

She says "Unfortunately we were only told that not all accounts will be able to purchase electricity online."

What's the criteria that was app****, why is the option on my profile if I can't use it.