I doubt you have 28 BTC for that.
We have private vendors that we work with who use our website for big transactions all the time.
Can you sign a message saying "Hi LoyceV, this is btcmiddleman.com proving we processed 28 Bitcoin"? Sign it from the address that held 28 Bitcoin a few days ago, and you'll get credibility instead of just an incredible story. If you don't want to post the address publicly, feel free to PM me and I'll confirm ownership of the address without posting the address.
although we can work these disputes as well
How?
Alice says she shipped 10 kg of gold, Bob says he received 10 kg of lead. How can you possibly know who's lying?