Buyer opened case claiming not received item

Description

Hi, A buyer has opened a case claiming she hasn’t received her parcel. I have tracked this and it has been signed for in her name on 14th august. I have uploaded picture of tracking receipt, a picture of the parcel with her address on it and the tracking sticker and a picture of the Royal Mail website with a signature in her name. Is there anything else I can do and what are my chances winning this case? Also how long do these cases usually take? She opened the case yesterday afternoon and I replied with all of the above but still waiting for a response from her