The answer is, if you agree to do this, you have to do it; the relationship between an independent contractor and his/her client is a contractual one, so whatever is agreed to between them defines the scope of the work and compensation.If there is a written agreement with a definite term currently in place, the distributor can't look to change its terms until its expiration. If there's no written agreement, then it's most likely the case that the distributor may make this a requirement of the work at any point going forward--and if you don't want to work under those conditions, your recourse is to stop working for him/her. Note that until you were told that the terms changed, you had to be paid per the previous terms or agreement.