Jump over to live chat and explain to them you bought the day sports pass by mistake and ask them for a full refund.
Use this link page below to find the green chat button to click on.
Hi, i have a similar problem (3 year old purchased a sky sports day pass I don't need). I have now added the payment PIN to prevent any further occurrences. However, the Live Chat option appears to be unavailable at this time
Try this link for Live chat. Just make sure to click "chat online" within the green box.
An alternative option is to send an email to the address in the below picture.