Toggle these two settings to true and false as per notification from Tennis for kids.

ASK_CLASS_REGISTRATION_FEE_ALREADY_PAID_QUESTION false
ASK_CLASS_REGISTRATION_FEE_ALREADY_PAID_QUESTION_TEXT I confirm I have paid the $20 Annual Club Registration Fee applicable for 2022. Do not tick this box if you have not paid your Annual Club Registration Fee. If incorrectly declared, you will be sent an invoice for the registration fee which will be due prior to beginning any program. (This fee does not apply to Special Events or Holiday Programs).

CLASS_REGISTRATION_AGREEMENT_CHECKBOX_2_ENABLED true
CLASS_REGISTRATION_AGREEMENT_CHECKBOX_2_TEXT I agree to being charged the $20 Tennis For Kids Annual Club Registration Fee (This fee does not apply to Special Events or Holiday Programs)

ASK_CLASS_REGISTRATION_FEE_ALREADY_PAID_QUESTION true
ASK_CLASS_REGISTRATION_FEE_ALREADY_PAID_QUESTION_TEXT I confirm I have paid the $20 Annual Club Registration Fee applicable for 2022. Do not tick this box if you have not paid your Annual Club Registration Fee. If incorrectly declared, you will be sent an invoice for the registration fee which will be due prior to beginning any program. (This fee does not apply to Special Events or Holiday Programs).

CLASS_REGISTRATION_AGREEMENT_CHECKBOX_2_ENABLED false
CLASS_REGISTRATION_AGREEMENT_CHECKBOX_2_TEXT I agree to being charged the $20 Tennis For Kids Annual Club Registration Fee (This fee does not apply to Special Events or Holiday Programs)

The system is set to charge the Registration Fee set from class properties.
In some parts of the year, they do not pay the fee by saying that they have already paid.
At the start of term 4, they will agree to pay this fee.