I had the same issue!! I'm a new customer who joined in February and kept being prompted to 'top up' my account in order to check voice mail, which I did more than once (paid €80 over 2 months) but still had no credit. When I contacted Support, I was told that I could only top-up by 10 or 15 euros. Otherwise, the money just went to 'my allowance.' When I asked if that meant I now had several months' allowance in credit, I was told that they could authorise a ONE-OFF credit of €20 to my account, but the other money would not be credited. I don't see that written anywhere.
I said (via Chat) "No thank you. No offence, but you obviously don't have the authority to resolve in an acceptable way for me." I've now paid 90 euros for 2 months for my 20 euro a month plan.
NOT GOOD ENOUGH, 3.
@CMW Anytime you top-up by €20 or more on the 3 Prepay 20 plan €20 is deducted for your price plan benefits. So, if you need extra credit for calling voicemail or international numbers for example it's best to top-up by less than your price plan amount. Take a look at All about: Prepay Plan Activation for more info 👍 In saying that, pop me a PM so I can take a look at the top-ups on your account and what the Web Messaging team have offered 👌