i purchase the smush it pro, and enable it, uploaded imafe

i purchase the smush it pro, and enable it, uploaded imafe with size of 370 kb, after smush it i check it iwas 371 kb, and it wrote reduce by 40 kb !!!!!!!!!!!
you plugin not working .
can you refund me please????????!!!!!!!!!!!!!!!!!!!!!!!!!
i do not want any developer to fix this issue on my website, as it not working !!!!!!
can you pelase refund me ?
and also if you want i can send you my detaisl, wp, to check by your self !!!!!!!