Acoustic Survey for Sound-proofing/dampening required between office walls

We have a small office in Hadfield where we have split up a larger room into 2 smaller rooms for giving online training courses. The builder used proper acoustic boarding and insulation specifically for sound insulation. Sadly this has not worked and we can still hear each other clearly between the walls. We want advice on what else is worth trying within our budget to muffle the sound more. We also want advice this time before we split the next room up into 2 on how best to do this to prevent too much sound travelling through the walls. We would just want a site visit to our offices followed by a very brief report detailing the requirements recommended.