This is caused by user IP capturing related security. Whenever secure sites (not limited to VoguePay) detect a change in your IP for the same session, the security feature will immediately be triggered and you will be logged out to prevent your account from hacking. Networks that do not use a stable IP are referred to as using dynamic IP. Dynamic IPs change at intervals of hours, minutes or even seconds and this makes their users unable to use secure sites conveniently.
Airtel is one of the networks that uses Dynamic IPs, we would therefore advise that if you are using Airtel network, kindly change it to another one such as: Etisalat, Glo, MTN, Swift or Spectranet and proceed with your desired operations on VoguePay.