Bookmaker changed odds after bet placed?

[Robtatse]

Hi all

I placed a bet this morning with a bookmaker on a football game. The odds I placed were 3/1 and it was a fairly large bet. 
 

The bet was confirmed and I could see it in the ‘My Bets’ section. I also have a screenshot of the bet with the odds.

Once the game was in play I went back into ‘My Bets’ and could see the odds had been changed to 4/5! I contacted live chat and he said he could see there had been a big change in the odds of my bet after placement.

It’s been passed to the traders and I am awaiting a response. 
 

Are they allowed to do this? I had already placed the bet so surely they can’t? Incidentally the bet won and paid out at the lower odds and I am pretty furious. 

Edited March 10, 2023 by Robtatse

[Fader]

They're allowed to do it if for example somebody is trying to manipulate by betting on a goal they know as happened and there is a slight delay. 

For example, if you're at a match and bet as they go to score in an empty net and you know that's going to be a goal. 

Paste your betslips pre and after