Holiday let deposit

Hello, we recently had a months holiday let with a certain well known agent but it didn't go too well. The original apartment was not as stated  and not fit for purpose, we were moved to another that we had to pay extra for. We stayed for 27 nights and ate out every day ,did not use any aircon, heating or cooking facilities. We have been charged £101 for the bills out of a deposit of £300. I did query this  before the return of deposit and have an email stating they have made an error but this has not been rectified. Is there any way we can make a complaint about this and who to. Has this happened to other renters who feel they have been ripped off with high utility bills . I have made my feelings known to the agent but do not hold out much hope of getting anymore deposit returned. We have visited Mojacar for the last 16years sometimes 3 times a year and this is the first time we have had something like this happen to us and we will definitely not be using this agent again.