With the outbreak of coronavirus causing financial issues for a number of football clubs globally, Sion president Christian Constantin recently informed his players - with one day's notice - that their wages were to be reduced.
Song had just three months remaining on his contract but refused to agree to the terms without speaking to his representatives first.
The 32-year-old - whose former Arsenal team-mate Johan Djourou was also dismissed - now looks set to fight against his dismissal and says he will go to Fifa in protest.
Speaking to RMC Sport, Song said: "We played a friendly on Friday [March 20] and we were supposed to meet with the president on Monday, then on Tuesday, he said. We had no news.
"We received a WhatsApp message on Tuesday afternoon to tell us that everyone had to sign a paper telling us that we were being lowered our wages, that we were going to be paid around 12,000 euros.
"We were to return the paper the next day at noon. We received this document without explanation."
Song explained it is not his job to fully understand the implications of Constantin's request and insisted he could not sign any documents in such a short period of time.
"I am a footballer, it is not my job," he said. "There are people to verify that. I couldn't sign it, we didn't have any discussions.
"All the clubs are talking today. Our captain didn't know anything. We decided together not to sign this document. We wanted to talk.
"I did not make any professional misconduct. All the clubs talk to their players to find solutions. We do not understand what happened. No one can understand."
Alongside Song, the Swiss players' union also believe the dismissals were unfair and have written to the club in protest.
"You have terminated the employment contracts of the players without notice by letter dated 18 March 2020," they wrote. "We hereby expressly protest against this termination without notice.
"We, therefore, expect you to withdraw these abusive terminations immediately and to enter into discussions on possible alternatives."