Not only is the HC12 data that is sent and received not error checked, so you have to arrange your own, you cannot definetivly control what the HC12 is doing, the on board micro has control really.
One of the packet based tranceivers, supported by the Radiohead library might be a better idea, RFM22B, RFM24, RFM69 or the LoRa devices.
With these packet based receivers whilst the software might cause you a bit more brain stress, you do have direct control as to what is happening at a low level, if you want an RX only for instance that is easy to setup, and the devices do support CRC checking of packets.