I've been using Instawallet for the last 8 months and never had problem. Just today I got 3 and 2 bitcoins from someone on different wallets and Blockchain confirms the transaction but there's no update in the Instawallet balance. While, on the other hand, I transferred 10 bitcoins from IW account to the other and it hasn't confirmed one transaction in the last 6 hours while again Blockchain confirms the confirmations from the network. What's going on? Is it a similar problem that happened before when the Hot Wallet was topped up? I'm hoping so.
Since you are still stuck in the newbie forum, I re-posted parts of this in the main Instawallet thread:
This is likely a technical issue which will be resolved eventually.