VBScript - Find files in folder by string in filename, move found to different folder

I am still learning VBS, not sure if I'm going about this in the correct, or most efficient manner. The test scenario is as follows, in addition to regular desktop items I've added three .txt files named:

"Tool - YouTube"
"welcome to facebook"
"BBC news"

When my code (bottom) runs it creates "Sorted" folder as intended (if it doesn't exist), but only the "BBC news" text file is found and moved by the 'instr' function. Furthermore if the "Sorted" folder already exists with "BBC news" text file within, then running the script will return.

Line 20
Char 2
Error: File already exists
Code: 800A003A

The script when working should find any files in a 'source' folder according to a search string and move them to another 'destination' folder. If a duplicate exists in the 'destination' folder, it should be replaced by the file found in the 'source' folder. Please can anyone explain what changes I should apply to get my script working?

dim fso, folder, newfolder, sourcefolder, destfolder, searchname1, searchname2, searchname3

sourcefolder = "C:\Users\...\Desktop"
destfolder = "C:\Users\...\Desktop\Sorted\"
searchname1 = "youtube"
searchname2 = "bbc"
searchname3 = "facebook"

set fso = createobject("scripting.filesystemobject") 
set folder = fso.getfolder(sourcefolder)  

if not fso.folderexists(destfolder) then
    newfolder = fso.createfolder(destfolder)
    wscript.echo "'Sorted' folder created in path: " & vbcrlf & sourcefolder
end if

for each file in folder.files
    x = fso.getbasename(file)
    if instr(lcase(x), searchname1) > 0 or instr(lcase(x), searchname2) or instr(lcase(x), searchname3) then
        fso.movefile sourcefolder & "\" & file.name, destfolder
        wscript.echo"Files moved to 'Sorted' in path: " & vbcrlf & sourcefolder
        wscript.quit()
    else
        wscript.echo "No matches found"
        wscript.quit()
    end if
next

Solution

Here you go, I fixed your if/then statements and added and if fso.fileexists:

dim fso, folder, newfolder, sourcefolder, destfolder, searchname1, searchname2, searchname3

sourcefolder = "C:\Users\...\Desktop"
destfolder = "C:\Users\...\Desktop\Sorted\"
searchname1 = "youtube"
searchname2 = "bbc"
searchname3 = "facebook"

set fso = createobject("scripting.filesystemobject") 
set folder = fso.getfolder(sourcefolder)  

if not fso.folderexists(destfolder) then
    newfolder = fso.createfolder(destfolder)
    wscript.echo "'Sorted' folder created in path: " & vbcrlf & sourcefolder
end if

for each file in folder.files
    x = fso.getbasename(file)
    if instr(lcase(x), searchname1) > 0 or instr(lcase(x), searchname2) > 0  or instr(lcase(x), searchname3) > 0 then
        if fso.fileexists(destfolder & "\" & file.name) then
            fso.deletefile destfolder & "\" & file.name, true
            fso.movefile sourcefolder & "\" & file.name, destfolder
        else
            fso.movefile sourcefolder & "\" & file.name, destfolder
        end if
    end if
next

wscript.echo "Files moved to 'Sorted' in path: " & vbcrlf & sourcefolder