Ask HN: "Cloud" based phone system for call centre

I've recently taken over responsibility for reorganising a support team and one thing that's clearly not fit is the phone system. It's decent for a normal office but doesn't have the things I expect from a customer support phone system. Basic requirements as follows:

1, More complex IVR capabilities to filter calls to appropriate people (based on language, skillset, next-best routing etc) 2, SLA, queue etc monitoring in some sort of way we can put on a screen 3, Historical reporting 4, Preferably some sort of API so we can scrape data and load into a datawarehouse for stat consolidation

Our current phone lines are all VOIP anyway so a off-premises/"cloud based system would be ideal.