Appointments+ not showing appointment times correctly

Hi there,
We are using the Appointment+ plugin on one of our websites -
We are having an issue as our calendar is not showing the correct appointment as they do not match the working hours of the service providers.
For example: under services Provider > Joan Ellsworth has working hours listed for Tuesday, Wednesday and Thursday - but Wednesdays are all greyed out for her - when though she should be available.
The 'general calendar' with no preference of service provider also does not display the correct appointment dates as there are blocks of time that are grayed out on Tuesday and Wednesday - even though we have working hours listed on these days.

Do you have any ideas on what the issue may be here?