"Send the buyer a message" during an open request

[mysterious_cities_of_mold]

If I use the "Send the buyer a message" option during an open request, can the request be escalated to a case by the buyer immediately after that or do you still have the option to refund the buyer if you choose? I don't know if you only have one chance to respond?

[4_bathrooms]

You can send as many messages as you want.

The buyer has the option to "ask eBay to step in" on the third day after opening the request regardless of any messages that have been exchanged via the case. Note that if a return label has not been issued via the case and the buyer chooses to escalate it's pretty much a given the buyer will receive a full refund, be told they don't need to return the item and a "case closed without seller resolution" ding being recorded against your account.