Connecting to home IP Camera from outside of home wifi network

Note: I checked the answers under Accessing IP cameras from outside network but I could not understand. Forgive me for being this dumb :S. I thought using port forwarding or vpn to home network should solve this issue but it didnt.

I have IP Camera Kaposev (Hidden Wireless charger camera) that is accessible from the iOS app HDWifiCamPro when both the camera and my cellphone is connected to my wifi at home. It works OK. However, when I am trying to connect to the camera using the same app remotely (using the 4g network in my cellphone), the app fails to connect. Can you please tell me what I should do to connect to the camera from outside of my wifi?

What have I done so far?

Using wireshark and my iphone connected to my Macbook (with RVI enabled and xcode installed), I was able to monitor the traffic between the Iphone and the camera. I see that the the communication is going over UDP between ip_addr_camera:28888 and ip_addr_phone:20988

The camera’s username is: SOME_USERMAME and password is: SOME_PASSWORD

My public ip of wifi (gateway) is 218.201.55.211

I created port forwarding in my router as following

Port forwarding 1: Name: Testcam Protocol:UDP WAN_port:20988 LAN_port:28888 Destination_IP:ip_addr_camera Destination_MAC:MAC_CAM

Port forwarding 2: Name: Testcam2 Protocol:UDP WAN_port:28888 LAN_port:20988 Destination_IP:ip_addr_camera Destination_MAC:MAC_CAM

I have enabled the VPN service in my router setting, and created a VPN in my cellphone. Hence, when I connect to the VPN in my cellphone, I get the public ip address of 218.201.55.211 and I get a LAN IP for my device as well.

After these steps I am lost. I am new to the whole networking thing, I will really appreciate if you can guide me what more should I do to be able to view this camera remotely. Is there any easy way to access the stream remotely? I do not know if my camera is ONVIF compatible or not

I am unable to access the camera from udp://ip_addr_camera:28888 or 20988