lodging complain agaist a trading broker

[WTFH]

Sounds like someone who doesn't know much about brokers.
They will sell for as high as they possibly can because they will get more margin. It's not their software, it's not them acting illegally. They are doing their job. If you think you can do it better, do it yourself.

[Lance]

The link you posted had as the first sentence 'We do not investigate individual complaints.'

You should take your complaint to the trader in the first instance anyway and give them a chance to resolve to your satisfaction.

[Lance]

The price you talk about is the price of the last sale. Your broker sells for the best price he can get. It may be more, or it may be less. That's called 'trading'. Good luck if you think you'll get anywhere with a complaint unless you can prove the trader deliberately undersold your shares.

[fullyautomatix]

Can you provide details on the trade? How much was it for? What did you buy? Did the price fluctuate a lot that day? What was the commission ?

[raphal]

Where can I do that ? Finance regulatory body ? Thing is when I executed a transaction, the opening price was much higher than the actual price. Probably issue with their software. I have a screenshot of the graph taken at the time I was opening the transaction, to prove my point (additionally requested audit data from the broker).

here: https://www.fca.org.uk/consumers/how-complain