It is not permissible to join pyramid marketing schemes, because they are based on deception, gambling and consuming people’s wealth unlawfully. See the answer to question no. 97880 and what it contains of references.
If a person buys some product and does not want to enter into this scheme, but the company brings him into it, it is not permissible for him to continue subscribing, because continuing in an invalid contract is like entering into it in the first place.
Hence the Prophet (blessings and peace of Allah be upon him) said in his Farewell Sermon: “The riba of the Jaahiliyyah is abolished, and the first riba that I abolish is our riba, the riba of ‘Abbas ibn ‘Abd al-Muttalib; it is all abolished.” Narrated by Muslim, 1218.
The Prophet (blessings and peace of Allah be upon him) stated that invalid riba-based contracts of the Jaahiliyyah were abolished and that it was haraam to continue with them, even though they had been drawn up before that, and in fact had been drawn up before the prohibition on them had been revealed from Allah. This is clear in the words of Allah, may He be exalted (interpretation of the meaning):
“So whosoever receives an admonition from his Lord and stops consuming Riba, shall not be punished for the past; his case is for Allaah (to judge); but whoever returns (to Riba), such are the dwellers of the Fire — they will abide therein”
And Allah knows best.