Extractor did not work on stud in cylinder head, so I used an angle grinder to grind the edges of the stud and then removed it with an ajustable spanner.... 
The Extractor did come in handy for the two studs stuck in the exhaust mount plate......
Worked a treat so not a total waste of money!
I'd take it back and honestly tell them that it would not do the job you bought it for and tell them you want a refund !
