As i can see you need a very simple system to record incoming calls, this can be done with some PBX, please contact me to discuss and will let my skills and experience here.
4 years experience in Asterisk, FreePBX, Elastix, Cisco, Freeswitch, Yealink, Snom, Grandstram, MyPBX, Zhyco, Virtual Private Servers, Hosted PBX, advance networking, Call termination, Dialers, CallCenter, Profesional working and long term support. Variety of VoIP devices like gateways GSM ATA FXO FXS T1 E1. I'm the general manager in a VoIP integrator of my country with a great reference.