CAN YOU HELP?? Iphone and chinese sim card!?!??

If anyone can help me I would be so incredibly grateful! I have been dealing and trying to resolve this issue for over a month now! Apple support just wants me to go to a store, but I cant! I moved to China a little over a month ago, I put a Googlefi sim card in my iphone 6s plus and have been working off that since I moved here. Googlefi service works great however it does not allow me to have a chinese phone number, which is essential to use many of the services here in China! So I got a Chinese unicom sim card, put it in my phone, it worked slow but okay for about less than an hour, and then it didnt. I was still able to get phone service (calling and texting) however I cannot get data anymore! With the chinese sim card in, my phone shows the cellular service bars, the cellular service it is on written in chinese characters, and the 4G symbol. However regardless of it showing that I have 4G, none of my apps including safari browser let me connect to the internet! My VPN wont connect because it says there is no connection! Just like every other app! They all say no connection!! I dont get it, why is my phone reading the chinese sim, allowing the cellular service to be used, showing I have 4G but not giving me any internet connection?

Things ive tried:

• yes my phones up to date on the latest software
• restart my phone
• reset my network settings
• tried a different chinese sim card and company (same thing happened, oh and I know its my phone because I tried both sim cards in someone elses phone and they worked fast and fine immediately)
• i talked to apple support several times, they just want me to go to an apple store for help (but heres the kicker, im in China and I dont speak good enough chinese to do that)

The only thing I havnt tried that I can think of is doing a complete back up onto icloud and then reinstalling everything back to my phone. Dont know how it would help, and dont want to do it because I have an HP laptop here, i dont know if everything would fit on that computer, would need wifi and it would probably take a long time.

So any suggestions? Any help? Please! **** if you make it work i would even venmo you money! Not kidding! I love my iphone, (yes my iphone 6s, i dont want any other iphone) but at this rate I might just have to ditch my iphone and purchase a chinese company phone.