Charged undisclosed fee on transfer between HSBC and Wise, each one stating the other has charged the fee

I work for a US company and get shares which are sold in US Dollars. In order to save on exchange fees I opened a HSBC USD Currency account. However when I tried to get HSBC to convert from USD to GBP into my current account the rate was very poor. So I opened a Wise account and transferred $1000. HSBC online stated they would charge $7 and deducted $1007 from my account, however only $975 reached my Wise account.

I have spoken to both HSBC and Wise and each one states that the other has charged the $25 fee. Although the fee isn’t a large amount, I’m annoyed out of principle. But also I can’t risk transferring any more USD this way since I could face further unknown fees. I asked HSBC what any future fees will be and was told they don’t know since they are stating that Wise charged the fees.

Can anyone give advice on what I need to do to trace who charged the fees. Also are there any alternatives to Wise that I can transfer USD to and that can give a decent exchange rate? Thanks s in advance.