HELP ME PLEASEE

Hello, guys. I am having very big trouble. So, I bought some Riot Points through a site BuyPCGame.eu because my card is not valid for Riot RP shop. I Bought the RP, I got the code. I am buying it from this site not for the first time. I tried redeeming the code, but it said that shop is not available. I tried again after 10 minutes. The same. After 30 minutes. Also the same. I tried and tried redeeming it until my account was on cooldown for 24 hours for redeeming codes. I tried redeeming the code on my 2 another accounts. Also the same. Can you help me guys? I contacted Riot with this question, but it's not answered yet. Maybe I am doing something wrong? I don't want to lose 3250 RP, because I payed 20 euros. Pleasee help!!! I want to buy zed :( [sg-janna]