It's very common for TfL to delay transactions even if you haven't travelled on a specific date. If you don't recognise a charge, you'll need to contact TfL about this charge directly. To do this:
Log in or create an account with TfL here
Once you're in, navigate to 'Add contactless payment' and add the details of your Yonder card. (You may have different reference numbers once your card has been added)
Select 'Journey & payment history, last 7 days only' and choose the journey you want to dispute with TfL
Select 'Contact us about this journey' followed by, 'I think I've been charged the wrong fare'
Here you'll be able to add any relevant and select reply by email