Canteen service

we are manufacturer and given some space to service proper for providing food services, breakfast etc to our 500 employee. the provider of service is big company and his head office at Mumbai. we are located at M. P., the provider is providing service at m. p. in our premises. my query is which type of tax will charge by provider namely igst or CGST, sgst. further in which category he cover under SAC and what rate of gst will applicable to them, further our premises is not AC. please clarify? regards. S. P. Tiwari