Welcome to the Community Forum and thanks for your post. I'm sorry that you are receiving duplicate allowance refresh texts every month.
To be honest, I haven't come across this before, but speaking with others on the Forum Team, have been advised that sometimes others get this as well, but only randomly.
I will investigate this further for you, so I'll need to take more information from you. I'll send you a private message requesting further details. Just check the purple envelope at the top right of this page.
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If anyone else is interested in this, I have had an exchange of private messages with Virgin staff and they concede that there is a "glitch" that causes some customers to receive multiple refresh acknowledgment messages but there is no agreed timescale for solving the problem.