Adding relay.nostr.band shouldn't matter - we crawl all relays. Zaps you send are published as nostr events by the receiver wallet (Alby in your case), and those are broadcasted to relays that your client specifies when creating a zap request. Which client are you using to zap? Please zap some event and send me a link to it - I will try to find out why your zaps aren't indexed. Thanks.