There is no option to control the satoshi/byte in there.
Robert just told me I could change it when sending money to my card.
Where is that option?
Hi Dangerous_Mind,
When topping up your card on our web app, a wallet address will be created for you to send us the BTC amount. You can copy paste the BTC address into any BTC wallet and choose the satoshi/byte. Your card will be topped up as soon as we receive the amount. This can influence the time it takes until the funds are on your card.
Best regards,
Robert @Bitwala
I thought on doing that but I wasn't sure if you had a process running behind the top up process so I made a regular transaction. I'll try it next time. Thanks

My mining pools usually make 1 transactions and they don't take much time to arrive to you. Usually less then an hour. I know if the mempool is full it could take more. But I can always check its progress so I'm ok with it.
Some days back I tried 100 again and it asked me for 8. Then I added more 150 in bitcoins to make the top up.
Then it asked me 17 for 250.
So I tried 200 and it asked for 12 and I made the transaction.
You should really check your code behind in calculating the fee it is very strange how it behaves.Thanks Robert