Unfortunately, we are unable to assist you via this platform. If you are not interested in using the Half Fare Card seamlessly, you should have cancelled the contract at least one month before the Half Fare Card validity ends. Otherwise, the contract is continuing, it cannot be put on hold and is therefore due for payment.
Please get in touch with the SBB Contact Center: +41 51 225 78 56. Only they are able to assist you.
For privacy reasons, you should not mention the customer number on a publicly accessible forum such as the SBB Community.