To sign for credits you will have to sort out your previous claim, as you can't sign for credits if you have a 2 year gap in your insurance record. You should have been receiving credits from the claim that you previously put in, even if you weren't entitled to a payment (and i wouldn't take anything that a welfare officer told you at face value, you very well may have been entited to a payment!!!).
At the very least you should have received notifcation of the result of your claim, I would be concerned that you didn't, and as this may have an impact on your ability to claim credits, this could well affect your pension entitlement. It may be daunting, but it is important that you sort this out.