yikes! that follow up doesn't make you look very friendly.

"to avoid anymore hassles". Seriously?

Fair enough that's what you think/why you did it, but do you really want other potential customers to think that any follow up service they may require will be considered a "hassle"?

You informed the buyer of delays AFTER they won the item. The listing never said anything before the customer decided to commit. The poor buyer probably thought you were trying to do a shifty on them.

Of course you should have refunded them, don't make out like you've done them any big favours!

Your reply could have been used to "save face" and potentially restore your reputation, something as simple as "Full refund provided due to unexpected/unforceeable events." That would have been a lot more comforting and trust provoking than "my customer's problems with my inadequacies were a hassle for me to deal with".