In the UK, firms that offer financial services need to be regulated by the Financial Conduct Authority (aka the FCA). You can check the Financial Services Register to see if your firm is authorised and exactly what they’re authorised to do.
The Financial Services Compensation Scheme (FSCS) protects your money, up to £85,000, in the event that your investment firm fails.
There are exceptions, for example, you are not covered in the event that your investment underperforms. This is simply one of the risks in investing.
FCA-authorised firms are likely to be protected by the FSCS and the Financial Ombudsman Service. Non-regulated firms or firms based outside of the UK may not benefit from this protection.
With investing your capital is at risk. Your investments may go down as well as up, and you may get back less than the amount you invested.