I had an XP-30 for about 9 years and paid one time to have a broken key replaced. It cost about $100.
I ended up having to replace more broken keys, but I did it myself since I couldn't fork out $100 per service.
You can get replacement keys from Roland for about $4-$5 a piece. The first time I replaced the keys myself, it was a little scary, but if you just stay organized and be carefull, it's pretty easy.
The lack of sound from the broken keys is probably due to the key not pressing on the specific sensor on the keybed. Same thing happened with mine.
The XP-30's are really well built boards, and I wish I would have kept mine.
The keybeds & action are superior to most new boards out, now. I'd go ahead & give it a shot yourself. Then, the next time, it will be no big deal.
When you order replacement keys from Roland, order a few of each - black & white, so you have them on hand in case you need them.
Good luck!
