As Vonage is a completely separate company to Wessex Internet, we are unable to assist with any Vonage customer services, billing or technical support enquiries.
However to transfer your telephone number to Vonage, you should be able to request this via your Vonage customer login or by giving them a call.
The process usually takes two weeks and most numbers can be kept and transferred.
Please be aware that when you do transfer your number to Vonage, this will cancel your BT line including any active broadband service. This is usually the desired effect for most customers, but some customers may need to be aware of this for timing reasons or otherwise.
Please find Vonage's contact details on their website - www.vonage.co.uk.