Sorry to hear this — both of those situations are frustrating, and the bonus leverage issue in particular is one that catches a lot of experienced traders off guard.
On point 1: this is actually a known trap with exchange-issued trading bonuses. What many platforms don't make obvious is that bonus funds are added to your margin balance, which effectively multiplies your notional exposure without changing your position size. So if you're running 5x on a 10x account and they stack a bonus on top, your effective leverage can jump to 20x, 50x, even 100x depending on the bonus-to-margin ratio. It's not always a glitch — it's often buried in the bonus T&Cs and the support team absolutely knows it. The "you ever futures trade before" response is a deflection, not an answer.
On point 2: unexpected liquidations at prices well above the stated liq price usually come down to one of a few things — funding rate spikes eating into margin, mark price vs last price divergence on thin order books, or the bonus itself being counted as margin that then got clawed back mid-trade. Zcash futures specifically can have spread issues that push mark price away from last price temporarily, and on a leveraged position that gap can be enough to trigger liquidation even when last price looks fine.
The fact that a later trade worked okay suggests it wasn't total platform fraud, more likely a combination of the bonus mechanics and the mark price issue on a low-liquidity pair. Still, not being able to get a straight explanation from support is a red flag in itself.
If you're evaluating where to trade crypto futures going forward, it's worth reading up on how to screen out platforms that use these kinds of bonus structures as gotchas. This guide on
how to spot the most common Bitcoin scams covers exactly the kind of shady platform tactics worth watching for.
Stick to platforms where the leverage and margin mechanics are transparent before you deposit.