First, was it the username or actual buyer name that was a string of letters? If just the username, then there's nothing inherently suspicious.
I see four potential scenarios using a business address:
1. The buyer is actually a business (who are we to judge what a business buys?)
2. The buyer doesn't trust home deliveries for one reason or another and chose to ship to their workplace instead.
3. The buyer is using a freight forwarding service. (Is their account based in another country?) If this is the case, you should proceed cautiously (Some will try to deny use of a forwarder because it voids the money-back-guarantee) but you're generally safe in these cases. We've shipped a handful of items to forwarders (we only offer domestic shipping), and try to make it clear to potential international buyers that we're not responsible for anything after the first delivery (so they need to be able to trust their forwarder).
4. The buyer is a scammer, using one of countless tactics to avoid paying for something. Does it happen a lot? Yeah. Can you avoid it without cancelling every suspicious order? Yes, as long as you follow the rules. Always pack well, and ship on time, with tracking. If a package is marked "delivered" and the buyer claims not to have received it, tracking proves them wrong. If a package is intercepted and redirected (by the recipient) the buyer (usually) can't even claim you sent the wrong thing.
All potential scenarios accounted for, I'd have shipped anyway. Handle everything professionally, and at the very least, eBay will give the buyer a refund out of their own pocket (hush money for sellers, the way I see it, to let scammers keep scamming).
