When Woolworths launched its Woolworths Mobile month-by-month mobile service in August, it said it also planned to maintain its Everyday Mobile prepaid option. But there's obviously been a change of heart, with Woolworths stopping new subscribers signing up to the prepaid service at the end of October and planning to switch off the service altogether at the end of March 2012.
This switch actually got announced at the end of September, but I only just got pointed to a Whirlpool thread discussing it. Woolworths stopped selling recharge vouchers at the end of October, and is giving customers until the end of November to redeem them. Woolworths says the switch is motivated by the increasing desire of its customers to access 3G data services (the Everyday offering is 2G only). The market changes fast; back in March 2010, Woolworths told Lifehacker that the "masses" weren't yet using data options.
Incidentally, the Whirlpool thread, started by a user who is complaining they are going to lose $150 of credit, seems based on a fairly whopping misreading of what's actually happening and what they're entitled to. Because the service is closing down, there's no longer the ability to roll over credit, but any existing credit will still be available for up to 100 days after Woolworths stops allowing recharge vouchers to be redeemed on November 30 (the exact period depends on the terms of the plan).
It's not an arrangement that it particularly likely to convince customers to switch to the cap-based Woolworths Mobile service, but it doesn't strike me as actionably unfair — you just have to use your credit within a fixed period, which is the basis of most prepaid plans. Realistically, a customer who wants a long expiry prepaid plan is going to look elsewhere rather than switching to the other Woolworths plan.