nice to meet u
I have ready callshop solution , which is multi tenant callshop solution,this need 1500$,this is installed on server side
if u need single tenant callshop solution ,it's also ok ,this need 200$,this will install on each callshop
demo is multi tenant callshop solution ,using a2billing as billing
yes,they can talk with voipswitch via SIP
see demo in private message