Hi there! Just need some advice. Basically had a quote of 4k for new bathroom. Paid the deposit upfront of £1800 several months back. Work now completed, they sent the final invoice of only 900, meaning its much lower than expected but I paid it and said thank you for the works and they replied with your welcome and that was that. Should we remind them that they have actually under charged us from the invoice? Or do we keep quiet? But then will they come back at a later date asking for the rest of the money that they appear to have mis calculated? Wwyd?