What can i do if my neighbour falsely accuses me of noise pollution?

My landlord paid us a visit yesterday to tell us that there were complaints against us. im 20 and my spouse is 22 we rent a house and work full time. we have lived in this house for 6 months and had 2 parties, one a house warming where the music was provided by a professional DJ who turned his equipment off at 11pm sharp. The second was a Christmas party which went a little later till around 1am. On both occasions the neighbors were invited. We arrive home around 5pm everyday and are in bed for roughly 10pm - 11pm. According to our neighbors we have the music on full blast every day which is simply untrue. We had an occasion a few weeks back where we had the music on whilst having a quiet drink it wasn't loud but at 6:30pm they demanded we turned it off so of course i told them to stop being ridiculous as it wasn't loud. Apparently they have the police involved and are seeking legal advice which is infuriating as we are doing nothing wrong. Please any advice on what we can do?