The position was for an ongoing freelance writing job. I completely understand that I read and signed the document, but can't help but think that it's a shady business practice. The earnings cover the month of February and I only stopped writing at the beginning of March. By including this clause, they're ensuring that any employee who leaves the company at any time other than the middle of the month (when they pay through Paypal), forfeits everything they earned. Thanks for your response, it's much appreciated.
"Conditional payment" clauses can be invalid when they are of the pay-if-paid sort. New York and a few other states have found that contracts that state an employee/independent contractor will not get paid unless the business gets paid by the client are not valid.
But the clause that concerns you is a bit different than this.
You were apparently hired as an independent contract for a writing project, and you were provided with the scope of the project and the project schedule (14 days). You read the terms and conditions of payment and you agreed to them.
As an independent contractor, you are responsible for the satisfactory completion of the job for which you contract. When you breach the terms of the agreement, this can release all obligations on the part of the other party, including having to pay - and you could actually be responsible for paying for any damages suffered by the other party.
That said, more really needs to be known about the commission-based website that hired you and the type and terms of your employment with the business (including a review of the contract in its entirety). It
is possible the business is shady and the business practices shoddy and the terms of the contract invalid and unenforceable and that you are legitimately owed $100+.
For that reason, you might want to take your contract for a personal review by a local attorney. Perhaps you can find a local legal aid clinic that will do the review for free (I am not sure you will find an attorney for less than $100).
Good luck.