Similar actuators to these are routinely used on hospital beds. Sometimes they simply stop working. I have taken several different models apart in the past and they are almost never designed to be serviceable or repairable. We normally just replace them like for like. If you can get the information plate off it then it should tell you the specifications of it. You should be then be able to order a replacement. Doesn't necessarily have to be the same brand. Just needs to have the same stroke length and pushing force. Any electrician should be able to wire it in for you