I need to know

I am the employer and chief representative officer of my company but as we stuck here in Nigeria, how am i gonna get the PU letter? As we are still stuck in Nigeria, i am paying my house rent, office rent and car park rent, and yet PU letter or TE invitation is needed from me before i return to China. So , my question is can i write my own and family invitation letter and stamp it with my company seal and show to Chinese Embassy in Abuja for granting us visa? Seconddly, Chinese Embassy in Nigeria is still not open, but Chinese Embassy in America, Europe and other countries had open, is there any reason why the Embassy has not open? Thanks as i wait for your reply because we never plan to stay this long in Nigeria, we just return for our usual chinese new year holiday and after like 2 weeks the covid 19 issue started , so we are kind of stuck and left my things in China