Write to them. Explain what you did and that you believe you have a qualified distribution and/or Rollover. At least two users, in this forum, have reported receiving a CP2000 letter, from the IRS, on 529 distributions. They replied that their child was in college and the distributions were for qualified expenses, which they listed, but they did not provide receipts.. They later received a notices saying they were in the clear. Others have reported that just sending copies of school statements satisfied the IRS.
Because of the uniqueness and uncertainty of your situation, you may want to consult with a local tax expert to help you prepare your response.
