If the buyer who paid £130 cancelled and you refunded, then the amount for that refund would be taken from your Ebay balance.
In a day or two, the buyer's payment for the strap will be released to you and your balance will return to what it was before.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)