yes i heard after 5minutes. I used maxis code too. Choose payment paypal then switch credit card suddenly back all gone. Gone cannot use. AFter 10 mins try works again

In my case, yes. My Maxis RM12 (unique code) was reinstated automatically about 30 mins later at 12+am today when payment failed the first time.

If the voucher has good value then you can spend some time writing in to them but make sure you have your transaction details. I've done this before and they gave me a replacement code.