Unreliable service

I was told my parcel would be delivered yesterday only for the delivery to be rescheduled to today. I called 3 times today to confirm that I would still get my parcel and was assured I would. At 5 I called only to be told the parcel won't be delivered today. There is no expected time of delivery meaning the whole day today I was at home not wanting to miss the parcel. This is completely unacceptable and the service very unreliable!!!