We are currently in dispute

We are currently in dispute over their neglect of my property despite paying for a full management service. They put in a totally unsuitable tenant with a guarantor of no financial substance and I'm now left with an estimate of £11k to put the property right. Belvoir say 'they didn't live in the property' and therefore not liable for the ongoing neglect. It has been a shocking experience as a landlord and certainly not a turnaround experience into being one due to their total mismanagement. I note they use the Belvoir awards to their advantage but the Belvoir central office claim Warrington are an independent office and are nothing to do with them.