How can I remove this notification? Sorry repairing at Apple was too expensive for me

You don't. You used unauthorized parts and left some needed ones out.

Apple will not touch the device.

I found this on ZDNet.com regarding your question.

If a display isn't genuine the Important Display Message appears on the lock screen for four days and in the Settings app for 15 days. 

Absolutely. They could also develop a true shatter proof screen. Just depends on which scenario is more profitable I guess.