Toilet not flushing.

Hey guys I am running out of ideas as to what is going on with our septic tank. We have lived in our home for roughly 4 and have had nothing but trouble. Our biggest concern is our septic tank since we are scared that it will start backing up and cause overflow. We have trip numerous times to reset it and unplugged the wires, tested it, etc. We have had some Plumbers come out here but everything they do has only been some temporary fix. Usually every few months we have issues with a toilet the is right next to the septic not flushing right. When I walk outside I can smell the sewage and even see little puddles of it seeping through the lid. And no it doesn’t need to just be pumped there is something wrong with it.

Please help me, we are so tired of this, and any advice would help.