I have a couple of phones on 30 day rolling contracts with Orange, one with 1GB and one with 250MB of data. When the quota is used up do I get charged, or capped, for any extra usage ?

I'm not sure actually cos I got my bill today and I went over my 1GB by 100mb and it hasnt charged me any extra or cut me off :/ but usually it charges £1 a day for every day u go over (thats what happened last time) - but im not sure why i wasnt charged