If you are not happy with your provider and you have your care arranged by Devon County Council you can contact Care Direct 0345 1551 007 and ask to talk to someone about this.
If you want to provide feedback you can also make contact here: https://www.devon.gov.uk/adultsocialcareandhealth/contact/
If you are not happy with your provider and you have your care arranged by Devon Partnership NHS Trust you should have been told when your service would be reviewed and who by.
You can also look at this page and scroll through the teams who you might need to contact: https://www.dpt.nhs.uk/locations?service=395
If you want to provide anonymous feedback you can do this here: https://www.dpt.nhs.uk/your-feedback