Binance: cannot send BUSD cross-chain from BSC to BC using BEW

I am US based, so the only way to transfer funds out from Binance Smart Chain (BSC) is through the Binance Chain Wallet (BEW), via a cross-chain transaction to Binance Chain (BC). Trying to transfer BUSD and everything works fine with small amounts. But whenever I try to transfer a larger amount, the tokens are returned to my BSC account after a few seconds. I am assuming that for some reason the cross-chain transfer failed and thus the tokens are returned to the sender. Has anybody else encountered this issue before, and is there any way to make it work?

Binance: I contacted the binance.us customer service several times and they just keep ignoring all messages. Worse, the tickets are immediately tagged as "solved" and then the system asks how was the customer service. You guys can do better than that. Also, in case it is not 100% clear, the high-level message that customers like myself infer from such experience is that Binance can at any moment block our funds on BSC, at Binance's discretion and without any explanation or replies given. This is actually exactly what's happening in my case.