I can build this for you. I have extensive experience building inbound and outbound dialer systems and I have experience building the web based front ends as well.
I have an in-house cloud based framework built on top of freepbx asterisk for VoIP calling, IVR facility and voice bots. It is highly customizable. The framework can be connected to any bot framework like dialogflow to provide voicebot solutions as well.
we can discuss more on your requirement and I am sure I can help you with all your needs with my framework.
looking forward to hearing from you soon.