most companies probably just have a fixed fee and their customer support isnt usually doing more than repeating standard answers
in recent days (hours), the number of unconfirmed tx spiked, this allows the miners to cherry pick the highest paying tx and still fill a block, so they do.
Agree there's been a huge spike, but even with a lowish fee (say bitcoind's estimatefee 6) things are still going through in a couple of hours. This has been 32 hours!
They do use a fixed fee - it's 0.0002 BTC each time - which is fine when there's 1 input and 2 outputs, a 300byte txn - but when there are 10 inputs and 2 outputs and it's 1550 bytes that simply isn't enough (IMHO). Kraken on the other hand charge users a fixed fee, but on the actual transaction they apply the correct fee.
However, can anyone confirm or deny my maths on the fee for this txn?