SVG Files being automatically resized

Can anybody give me a bit of advice please.I recently bought an SVG file(just svg) from Etsy.When I cut the file it would not assemble correctly so I cu another just to satisfy myself that it wasnt working.I contacted the seller and to cut a long story short he says that because I am using Lightburn it will automatically reduce an SVG by at least 20%…which probably explains why it wont assemble the way it should.Can any one tell me how to stop lightburn doing this by whatever means.I hope I have explained it clearly enough.I did buy a file earlier in the year and the seller did say that lightburn would automatically adjust the file.But he gave me the measurements to enter so it worked out ok.Thanks for any assistance.