Chas, I don't think I can be much help here. I'm not very cell phone savvy. I have a very low-end pay as you go cell phone which is only used when we are traveling or if I'm out of the house without my husband.
I do know that there are programs available that can recover deleted files if nothing has been "written over" the space on the card.
Here are some recommendations for programs.
File Recovery SoftwareI can't vouch for any of them because I've never used them. I think, Chas, in your case, if you end up doing this, you would download the program to your PC, install it, then put the micro SD card into the card reader slot on your PC and have the software read the contents of the card and attempt to recover any data. As you may know, deleting a file from an SD card or from a PC doesn't fully delete the file. It remains there until the space is overwritten by new information. That can happen almost immediately if you continue using your PC after the file deletion or it may take a while. If you take the micro SD card out of your camera you won't overwrite any remaining deleted information and the chances for file recovery are better.