Just to clarify a few things... I've had a chat with OP via Skype...
- OP can copy/paste bitcoin addresses fine - so, no clipboard malware
- The transaction that has "gone missing" was sent to AddressX
- The OP sent another transaction to BitPay which also went to AddressX but was credited OK
- The OP has another deposit to BitPay that was sent to a different address and was credited OK
I suspect that the issue is with BitPay's system and it failing to credit deposits correctly for whatever reason. I have advised the OP to contact Bitpay Support and see if they can investigate why the deposit has not been credited correctly.
EDIT:Ok... so as it turns out... the culprit was actually "Electrum Pro"
Unfortunately, the OP had received some bad advice from a third party and had been using "Electrum Pro" to pay the Bitpay.com invoices received when funding their Bitpay card. On further investigation, there had already been a few other instances of funds being stolen... but for much smaller amounts that the OP had not noticed.
There was a pattern where OP would transfer to Electrum Pro, Pay bitpay.com invoice and then any leftover funds would be transferred out at a later time. Unfortunately, this time, the scammers saw the deposit and transferred it out before he sent to Bitpay.
OP is now using
bitpaydecoder.org to decode bitpay.com invoices to a BTC address+Amount so they can simply pay directly from their original wallet without needing to use an intermediary wallet like Electrum.
TLDR;
- OP got scammed by "Electrum Pro"
- Bitpay not at fault