with the "old" style contracts your monthly payment will continue until you request to change :
"3.4 At the end of the Minimum Term: We may contact you towards the end of your Minimum Term to let you know that the Minimum Term is due to come to an end. At the expiry of your Minimum Term we will continue to provision you with your Contract Allowance on a monthly (or other periodic) basis and will continue to bill you for the Charges. If you wish to change your Contract Allowance at the end of the Minimum Term then you can do so by contacting the Team but you will need to sign up for another Minimum Term. You will need to contact the Team at least one month before the expiry of your Minimum Term or any subsequent monthly renewal date for your Contract Allowance if you do not want us to continue provisioning you with your Contract Allowance each month. If you do contact us we will not provision you with your Contract Allowance but will continue to provide you with the Services at the rates set out for Pay Monthly customers in our Tariff Table until this Agreement is cancelled by either you or us in accordance with Clause 10."
It's your responsibility to notify Virgin if you want to change your plan one month before the end of your contract period.
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