11:05 AM -- We reached out to "The Doctors," which footed the bill for Aaron's rehab. They tell us, "The Doctors are saddened that Aaron did not complete the treatment we provided, as reclaiming his mental and physical health should be his number one priority. Although we are not continuing our work with him, we truly hope he gets better and is not negatively affected by outside influences.

Aaron Carter has bolted out of rehab after less than 2 weeks because he has to deal with some urgent matters.

Aaron's rep, Steve Honig, says, "Aaron has left the facility where he has been working on his wellness. Several legal and personal matters arose that required his immediate and in-person attention." Honig would not be more specific about the legal issues.

TMZ broke the story when Aaron finally decided to check in for substance abuse treatment. Police had made multiple welfare checks on the singer last month, and family members told us they had serious concerns he was relapsing.

Despite his shortened stay, Aaron's rep says, "He is still very much committed to his wellness and will be continually working toward being the best person possible.”