What is the ruling on money obtained for years of experience, and do the three incorrect years count as compensation for the three years in which a certificate of experience was not obtained?

You erred in obtaining a falsified certificate of experience, and you must repent. As for the ruling on the money received for each year of experience in the new job, it is considered as follows:

If the employer only considers experience, then the amount appears to be permissible.

However, if the issuing body of the experience certificate is significant, then you must inform them of the truth of the matter for the money to become permissible for you.