I am having a hard time following everything happening here. What is all this about hotspots and your neighbor’s router? Do you not own a wifi router? Most wifi routers will also have ethernet connections on the back. I apologize for not understanding. Edit: I am guessing by “I do not have a lan line” you mean that you do not have a working internet connection at all at home? I am confused as to how you intend to run a server permanently over a phone hotspot.
My one thought is: have you gone into your router and reserved a static internal IP on your LAN? (e.g. 192.168.0.##)? Often servers and things will lose communication if their internal IP changes and your devices cannot find them.
Also, if you are porting out onto the public internet, are you using something like a dynamic DNS so that your devices can route to your public IP? your public IP will be constantly changing, so you need some way for your devices to find it.