No Feedback on Repairs for 3 days

Our Merc C180 Coupe was booked for repairs on Friday 26 January 2018, which was a return job on an aircon repair done in December 2017. No feedback or status was provided throughout the day by the service advisor Edward. In the afternoon we called to enquire status and was only told then the car will have to stay overnight and might be ready on the following day (being a Saturday). On Saturday, still no feedback or advise when can the car be collected. We called around 11 or so and were told Edward is not in and therefore no work has been done on the car. The following Monday, still no feedback/advise from Grand Central Motors so again we called and Edward promised to call back with details and did not do so. On Tuesday morning, we called the Service Manager and promised to get Edward to call within 30 minutes and has not do so again. This is not only poor service but disrespect towards us. It's now 45min later since talking to the service manager and no call from Edward???