All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.
It is not permissible to obtain certificates unrightfully, as it involves lying, forgery, and deceit. Allah, the Almighty, has said (what means): {...And avoid false statement.} [Quran 22:30]
In Saheeh Ibn Hibban it is reported that the Prophet, sallallaahu 'alayhi wa sallam, said: “He who deceives us is not one of us, and deceit and treachery lead to the Hellfire.”
Based on this, purchasing that certificate is not permissible, and you should not use it or present it to get a job or for any other purpose.
We advise you to strive to obtain a genuine certificate if possible or seek employment that does not require what you don't possess. Fear Allah and exercise patience until Allah provides a way out for you, as Allah the Almighty says (what means): {And whoever fears Allah - He will make for him a way out and will provide for him from where he does not expect.} [Quran 65: 2-3].
Allah knows best.