If your goal is making money and/or securing a partnership you have to put yourself into a position of strength. The best way to do this is to launch an actual Chinese competitor yourself. This should cost no more than 10k USD per month assuming you can leverage your existing code, which makes it much cheaper than going the legal route. Feel free to contact me (contact info in profile) if you need help or introductions to people who can actually make this a reality for you in a week or two. I'm in Beijing and have done three startups in China and can put you in touch with people here who can actually help you.
A live product from you poses an existential threat to your competitors and keeps the big IT company from delaying in perpetuity (the typical modus operandi for big players here is to have middle management rush to agreement on the general principles of possible cooperation and then stalling and never doing anything more substantial -- the delay means they aren't sure if it is worth their while to clone you yet). But the threat of your getting actual traction matters because growth puts a deadline on your willingness to accept other people stalling, and your presence starts imposing actual costs on the startup. Those guys will need to change their branding at a minimum since they can't build an independent brand with you in the market, and once they know you will play hardball you will find them a lot more amenable to compromise if you want to go that route. With that said, if your market reception is good you may not even want to continue talking with them, since most Chinese startups are really inefficient and you can probably blow them out of the market anyway.