Cancel a return request

[gilwell-1]

An international buyer started a return request on an item they bought from me.  When I sent a message inquiring about the "defect" they said they had opened the case by mistake -- they meant to choose a different purchase.  Is there a way they can close or cancel the case?  He has tried calling eBay but gets a recording -- no live help.  I searched but came up without any concrete direction short of just letting the request time out without asking eBay to step in and mediate the return.  Any guidance is appreciated.