A credit what?

It’s a big deal over here and effects all sorts of weird things. They run on this system of 3 digit credit rating score. Ours is the worst at 000, good is 700 perfect is around 730. Until we get ours up to the +550 mark, we are fighting hard with most money matters. (Buying a mobile phone for example). We have just applied for a secured credit card. They have taken 1000 bucks of our money, locked it away and given us a credit card with a  1000 dollar limit. We have to be careful to  not pay it off, if you pay it all off when its due, then you never have any money out on loan, so they cant judge if you can be lent money, because you never actually borrow any money. So we are going to put about 400 bucks on it, and then just make the minimum payments for about 3 months. Then pay it off and put a different amount on it, then make those minimum payments for about another 3 months. In 6 months we should be a lot better off with a reasonable score. This is the only way we can build a score. Paying your electricity and gas does not count. In 6 months we should be able to move to an unsecured card and get our 1000 bucks back. Crazy to us, but normal to every one here. Parents do all sorts of weird things to help their teenagers build a credit score before they go off to uni and move out of home and things (other wise they cant rent or buy a car).
Just another of the joys of arriving mid life into a country with very different systems  than the one you grew up in……