It isn't Clear Channel. Clear Channel may be a partner on tours (their legion of former regional promoters provide logistical assistance in North America and no doubt CC is an investor).
Cohl dreams up a new corporate moniker to go with each tour (be it U2, Stones, Floyd) which makes him/them harder to track down.
Suggest you contact them thru Stones PR which I believe is still handled by Rogers & Cowan in NYC.
It's been my experience a professional request is at least acknowledged and forwarded by them. That's their job.