Lack of communication

There were multiple timeslots scheduled for fibre installation at my complex on a certain date. The tenant chose the most appropriate timeslot and made themselves available for the installation. Accelerit then rescheduled without informing me about this and left the tenant waiting for them to come through. I had to call Accelerit who then confirmed that they rescheduled. They then sent a mail the next week indicating that the unit had been rescheduled for a certain date/time, without even consulting to see what the appropriate time would be. When I rep**** to their mail and indicated that the tenant is only available earlier in the morning, they rep**** that all the earlier time slots were taken. When I then emailed to ask what other dates/times are available, and I indicated how this is very inconvenient, I didn't get a response at all.