Is working in data entry for a furniture website that operates on an installment system with a late payment penalty considered participation in sin or bearing witness to usury? And what is the ruling on increasing the price by 40% compared to purchasing from the agent?

If the questioner's job is merely to enter data onto a furniture sales website, and she has no relation to the transaction itself or to the condition of a late payment penalty, then she is not considered a witness to usury nor a scribe of it. The responsibility for that falls upon the two parties to the contract and whoever directly assists in it by writing it or bearing witness to it.