As far as I am aware of, NameCheap is currently fully operational and accepting orders (I just tested it). It's possible we were down momentarily for updates earlier this afternoon.
We do not currently accept PayPal payments but it is a feature we would like to add in the future. I can't give you a specific timeline or make any promises, but we'd like to implement it within a few months. We're working on a lot of new updates right now which you will see within the next few weeks.