Refund

[thaily.livejournal.com]

Sorry if this is too off-topic but I thought you guys might know something about refunds.
Due to personal issues I think a commission is taking too long, and the customer paid me well to do it. However due to a recent turn of events (which I could not forsee) I hardly feel like drawing anymore at all, can I just give a refund without consulting my customer?
I don't want her, who is a good customer and a good friend, to be a victim of my current listlessness and plan to offer her to finish the commission at a later date when my muse is back with no charge.
Who here has given a refund before and how? How was it received?
A little help here?