Applicability of GST on RCM for Availing GTA service in which the goods purchase is exempted?

one of my client engaged in the whole sale business of supplies of taxable and exempted goods they availed the GTA services in f. y. 2020-21 in which the goods carried in carriage transport is exempted so my question is that whether RCM is paid on GTA services in which the goods carried is exempted and if not liable to gst then any Tax paid on RCM bonafiedly is required to be reversed or not please guide me properly