I’m playing Rock Band 3 and completed a Goal. What do I do with these coins?

You can complete Rock Band World Goals while playing Rock Band 3 --some Goals may even be specifically created for Rock Band 3--   and you’ll earn badges and coins on your Rock Band World profile.  The coins you earn for completing Goals are used to purchase Power-ups in Rock Band Blitz; if you don’t own Rock Band Blitz, the coins will just accumulate on your Rock Band World profile until you buy and link Rock Band Blitz. 

• I didn’t get my coins for winning a Score War! I want my coins!
• What do coins do?
• My friend asked for my help but when I clicked, it said “Goal not found”. Where is the Goal?