Mom is not cooperating with carers coming in. What can I do?

Mum has a carer coming in 3 times a wk for half an hour they are here for her personal care but mum treats them like cleaners? I had apts this week and the agency rang and said noone was home so now mum is hiding on the carers and wont let them in if im not here?
When the carer does come shes supposed to help mum bathe OR make her bed up mum refuses to let her do either so she will just wash a few dishes and leave i mean what else can she do if mum dosnt cooperate?
This service is free and is part of the health system basically if mum keeps refusing she will be taken off the "system"? its taken me 3yrs to even get them to come and now mum is causing so many problems how can i make her see this is important and she must cooperate?

I dont know if anyone else had this problem but now hiding and not letting them in is just too much!