Writing a Seminar Paper — Chol HaMoed

Is it permitted on Chol HaMoed to prepare a Torah seminar paper for someone, after I promised that it would be ready during Chol HaMoed and I postponed part of the work to Chol HaMoed, and the client needs the paper literally just a few days after Chol HaMoed, and I will not have time to prepare it after Chol HaMoed? What if I ask for payment only after the holiday?

Shalom u’vrachah 

If you will suffer a loss as a result of not working on Chol HaMoed, it is permitted. 

If it will only reduce your profit, it is forbidden. 

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