Unfortunately, AIPRM don’t have the time and money to invest in becoming their own credit card processor. That process is ridiculously filled with bureaucracy, regulation, etc. Instead, like most others online, AIPRM rely on third-party processing. Those third-parties are the ones who accept or decline credit cards.
There is a HUGE amount of fraud online. Cases aplenty of people trying more than 30 stolen credit card details in a row trying to find the one on the list that might work - because hacked or stolen credit cards are sold in lists of thousands. AIPRM has had its share of exactly this kind of attempted fraud, and the only thing that stops it from happening is those third-parties that check and verify. From what I understand, AIPRM feel confident in the security of their current providers, and really don’t want to risk that security in trying out alternatives who’s sole credential is being more lenient and more trusting.
There will, sadly, be a few edge-cases. I have no idea why the companies that have accepted tens of thousands of other subscribers have turned down all of your payment methods. I doubt anyone that works for AIPRM knows either. Perhaps you’ve had a card need to be cancelled in the past, perhaps you use an ISP that hundreds of fraud cases have been done through, but for whatever reason, a company that doubtless would like to make money has some reason for declining your card - and that is their area of expertise.
AIPRM is a mass-market service. A million users. Way over 10,000 paid subscribers. All for a relatively small company that is trying to work on a great product but in an area where the entire landscape is shifting and changing with every moment. They have to focus on the service, on keeping up with all the changes, and even trying to predict what is coming next, with a small agile company. They simply don’t have the resources to handhold every transaction, and have to rely on trusted third-parties for many things. It is those third-parties you have an issue with.
I have a few friends in South Africa, so I do have sympathy. Your country is struggling from decades of corruption, where even the power services are unreliable. You have strict limits on imports that can make it difficult just to keep up with technology. And yes, it can be exceptionally difficult to pay for a great many things, as quite a few essential financial service providers refuse to deal with South Africa at all.
These are not your personal problem, of course. You have no control over that stuff. But likewise, this is not AIPRM’s personal problem, nor their fault either.