Always establish a dialogue with the seller. Will he agree to taking the goods back and returning your money if you aren't happy with the goods?
Now, I know your question is really about the payment form and the only thing I can think of is:
1. A good escrow service.
2. Send a cashiers cheque (aka Certified Bank Check in the US)
I had the above sent to me once when I was living in Sweden
from a US buyer. I asked my bank if the cheque could be
cancelled and to my suprise they said, yes!! If I send a bank
cheque to the US I cannot cancel it once it's been received and
cashed. However, a person in the US could still cancel his/hers
even after I've cashed it, as laws and systems are different
in the US....Sooo, if what they said was true, and I asked also
the international department of my bank and was given the
exact same answer, then you are fully within your rights to
cancel the cheque even after it's cashed and the money is
will be returned to your account. Your bank should be able to
confirm if this is indeed the case. I was told that the payee
could cancel the cheque during the period of 30 days after it
was issued. As such, I made one US buyer wait the entire 30
day period before I sent the goods to him, as their value
totalled over $4000 and he had zero feedback
Hope this helps.