Indecent rates

in all my swapps I always sent first , without giving my address until the other has received their coins, or until the receipt of emails sent.
I have two negatives votes, one for not answering quickly, having to check the valuation of a list of more than 50 coins, the other for not accepting a change of 4 blackmail silver IXX century, for 12 coins as vf - f, whose market value as of 16.25 € UNC was.
Now I find myself with two shipments, in which I ask for the shipping certificate, and the other part said it's better ordinary post, and now they have lost.
I must to vote negative, or I have to believe in the good faith of the people and think you really are lost.

In another exchange, I send 8 coins, without giving my address, only got 7, (it seems), that need is 1 cent for Finland (negligible), the other part tells me to wait my answer before negative vote for me,
resubmit a coin (to Australia), no answers, and I still do not give you my address.
I vote for him negatively ?.
I think before giving negative feedback, assess whether the other party has tried to deceive you.

I always sent first, I'd rather lose some money, before anyone thinks I cheat.