Proposal credit not refunded

Hi,

I sent a proposal for a job offer, but the next day the seller changed the description, which pushed the job offer outside of my competencies. I received an email letting me know that if my proposal is not adapted anymore I can cancel it and send a new one for 0 credit. I withdrawed mine, but haven't received the new credit. As mentioned I can not send another proposal to this project as it is out of my scope now. 
How does it work in this case? The clarification added by the seller completely changed the job, and it wouldn't be fair that I lose a proposal credit because of their mistake.

Thank you

Joyce