My installation was perfect guy was on time he communicated well with me and was very happy with his service

My installation was perfect guy was on time he communicated well with me and was very happy with his service. However I'm not so happy because only when he was here I realised this was not the product I initially wanted. I asked the consultant to call me back on Monday so we can sort it once they have listened to my recording but they havent yet. So I'm a bit upset that I have a contract on something that doesn't cover all my needs