LC43102

Hello, In August 2023 I paid just under £20,000 into an ISA with Bank A. Then in October 2023 a family member paid in ~£5000 to a loyalty ISA account I have with Bank B, with us forgetting this account was actually an ISA too. I used this money to travel. Obviously, this means the £20,000 limit was exceeded for the tax year 2023/24. I have only just realised this happened and so the money I used for travelling from Bank B has now been spent, and the Bank A ISA has been accruing interest ever since and is set to mature soon. What happens to my money now? Will I lose the money? Will I pay tax on interest gained over the £20,000? If so, how does that all work? I find this all very confusing so any help would be very much appreciated.