This is a guide how to deal with the rebel medics (Not sure if there is already one but yolo)
First to deal with heavy/medics is place your squad center in your base where shield generator protects it. The unit that would be most recommended to request would be snipers since they 1 hit K.O everything (atleast for me). Once enemies deploy the heavy+medic, your snipers will come out and snipe them. Your snipers would be under the shield generator so it makes it hard for their star ships to target them. Put traps in corners of the maps in case they try to bait you. Make sure the snipers your squad mates donate are high level. Other units you could try in your squad center are units that do extra damage to infantry but make sure they don't drive outside of the shield generator. This is my guide, I hope it helps (maybe).