I had to make a payment with bitcion to a wallet with specific amt. I made exact payment, but price bitcoin was going up. But my transaction was still unconfirmed till the evening. They rejected my payment bc the payment was a $3 more when they confirmed it.Can the price change if your transaction remain unconfirmed for a couple of hrs. It
In terms of value, the Bitcoin network knows only about satoshis and has no awareness of what other currencies (JPY, AUD, GBP, EUR, USD) peg to against it.
So when you create a bitcoin tx to send value to another party, that's always denominated in satoshis on the network; that doesn't change at all.
As you've observed, the dollar value may change if you paid a low tx fee, or the network was busy for the fee you paid, and therefore by the time it is mined, more dollar value may arrive, or less.
You've got a few options to avoid this - one is to pay a higher fee to reduce the time you're waiting for the tx (make sense on large valuable purchases), or to use the Lightning Network where fees are lower and settlement is near-instant.