IHS keeps declining my payment

Hi I am trying to pay the IHS and it keeps being declined. I have the money, everything is correct, I called my bank and they don’t even see an attempted charge on my account. I am an international student from the US and I read that the IHS does this A LOT. I have enough money saved up and I can definitely afford it. I have been using bonuses from zimpler casinos all spring and now my balance is quite plus. If they asked for a statement of my accounts, they could see for themselves. So why don't they explain? I am not sure what to do I just wanna be done with the student Visa application process i am going crazy!