Something similar happened to me. I had just finished a boss event and had several hundreds of gold. Then the next day I came on and only had 7 gold on my account.
I emailed support and they told me they would forward it to the developers, but after that I never heard back from them again. I sent several emails but after the first
never got a reply again.
Also, I have had similar things happen with cash on my account. (Although it has been a long time since this has happened.) The disappearance would happen when I would
either withdraw or deposit my cash from/to the bank. I am aware of the 10% deposit fee, so I know its not that, and I always checked to make sure I wasn't attacked or
something. I never really complained about the cash because even if its 100mill, although annoying, I didn't take it as a big deal.
I'm sure Pixel Addicts has ample income for a decent customer support staff or at least get one guy that will eventually get back to you and help. How do I know? Because
I paid their salary this week alone.