I was buying stocks on the LCN stock exchange and i bought shares BUT when I bought the shares and finished the process it said that my portfolio is empty and i just wasted 30 million. What the happened?
This does seem to be a common bug as seen in the GTA rockstar community, there does seem to be the occasional fix that buying a small number of shares that disappear means that it wont happen again, and some say that its avoidable by not using the escape key to quit the browser, however I am having difficulty finding any kind of official Rockstar support on the matter.
If you haven't already auto saved, you can go to your GAME settings >then go to LOAD GAME>then go to the last time you AUTO SAVED. If this puts you back to around 30 mil, then go to the debonair stock and only buy about 5 stocks, those will disappear, but after that you can invest in it all you want.
Are you using a pirated version of GTA 5? This is something that happens with pirated versions, info in the discussions on this Reddit thread on pirated GTA V stock issues.
Always buy ONLY 1 stock when you want to invest. It won't be there in your portfolio, but the second time it will be there. If you see it in your portfolio than you can safely buy more stock from the same company.