So, situation is even worse than it follows from OP. It turns out that topic starter runs a gateway which is not very efficient, and tries to solve his problem at a cost of bitCNY holders.
Magic wallet is not just a gateway running by someone, it's a free market like the Dex. Everyone can offer to exchange fiat CNY with bitCNY and vice versa with Magic Wallet (the software). Traders compete with each other. If one trader's price is not fair, people will go with others. It should be the most efficient. If it become inefficient, it means the pegging mechanism is flawed.
The fact that magicwallet users pay more CNY for bitCNY means that more users deposit funds into bitshares than withdraw through your wallet.
To bring the bitCNY price on par with CNY in your wallet, you need somebody to withdraw their funds through magicwallet, then deposit them back through other gateway.
Looks like you're saying "the market is acting wrong".
No, this is exactly how the market is supposed to work. If you have a mismatch between the deposit volume and withdrawal volume at your gateway, the price get skewed. You need arbitragers to correct it. Total supply of bitCNY has nothing to do with this, you can buy plenty at discount on DEX, it is your gateway which has deficit.
"you can buy plenty at discount on DEX" but only with BTS, you don't have that much BTS and nowhere to get that much with fiat (and even BTC). The on/off ramp is designed for the peg, where you can buy bitCNY with fiat CNY.
So what? To short bitCNY you need even more BTS than to buy it. How is messing up offset supposed to fix the peg at your ramp? This is ridiculous misthinking.
I don't know why you keep saying it's "my ramp" or someone's ramp. It's actually a decentralized p2p ramp.
A successfully pegged bitCNY means everyone can exchange fiat CNY with bitCNY at around 1:1 and vise versa with anyone else without need to worry about profit or loss. Ideally for a ramp the exchange price should be more than 1:1 on one direction but less than 1:1 on the other direction. Currently both directions are operating above 1:1 (Note: in a free market but not a simple ramp that the owner sets arbitrary fee rate), which means the peg is slightly off, which means the feed price is wrong, which means bitCNY holders are now taking advantage of bitCNY producers (shorters), which is unfair. To get mass adoption, we need to eliminate this unfairness, either by correcting the price feed, or by adjusting the force settlement offset.