I see only one solution on the referee issue for Mr Savvidis. The solution is to hire PR-firms in Western Europe and perhaps in the US, that will produce reports in major Western news and sports news outlets (this will cost a lot of $) which will reveal UEFA's complicity in the corrupt and criminal activities in the football leagues in Greece and other European countries which UEFA presides over. This will hopefully create a reaction in Western Europe by consumers who will abandon or degrade UEFA's and its sponsors' product, that will be a push for them to actually wanting to compromise or fix the situation in the Eastern European leagues and thus their image. The only thing that psychopathic mafias like UEFA and their sponsors pay attention to is their own interests (power and money). You hurt their interests by discrediting their product, showing that they're complicit in illicit activities, and you disseminate it to people who consume/watch the Western European leagues where the big money is and where most of their income comes from.
The other thing I've heard is to use violence or the threat of violence against referees and their bosses. That cannot be done by anyone even close to the Savvidis family. Otherwise they will come after them with judicial (or other) means and get rid of them for good. As you saw perhaps last week, PM Tsipras was hanging around with US Ambassador Pyatt who is the former Ambassador to Ukraine and one of the coordinators of the coup there in 2014, there are powerful people wanting Savvidis out.