Looking for TLS extensions on https://billing.cnservers.com
ext 65281 (renegotiation info, length=1)
ext 00035 (session ticket, length=0)
ext 00015 (heartbeat, length=1) <-- Your server supports heartbeat. Bug is possible when linking against OpenSSL 1.0.1f or older. Let me check.
Actively checking if CVE-2014-0160 works: Server is vulnerable, please upgrade software ASAP.