Ladbrokes complaint: Gaming bonus

Hi. I recently joined ladbrokes to do football bets. Today i won £77 and later i got a message stating i had £50 gaming bonus i could use. I opted in and went into a game and without my knowledge they had merged my actual balance of £77 with the free bonus for gaming. I played until the bonus ran out but when i went back to the home page my balance was gone!!! I went into that game for fun to use the bonus. Why did they mix it with my real money and when my bonus was used up i wasnt informed or askwd to use my balance to continue. Any other free game ive used will state when ive used a free play do i want to continue and use my money but this game didnt. I am actually broke and i have a kid and im a single mum. I was going to use that winnings for a food shop!! Its very sneaky what they did mixing my money with the bonus amount.