Usually, you get a text every renewal, along the lines of 'thank you for your payment' every 30 days. Did you get a text reporting the new plan's amount that was withdrawn? It sounds like the website is behaving as intended, but if you want the plan *now*, you can always choose to activate the plan immediately instead, but you forfeit the remaining term in the current plan you are subscribed to.
While I haven't responded to the text message myself, I'd first take a look at your wife's plan renewal date - they change regularly, since PM sells 30-day plans, not monthly plans. I'm going to take a guess and assume your renewal was sooner than you thought.