Tenant caused clog, sewer backup MOLD damage and is suing me for deposit and last months rent and still lives in house, is this legal????????

My tenant caused a big clog in the sewer drains that caused a backup under the kitchen sink with sewer water up through the dishwasher vent pipe and down into the basement that then caused water damages and MOLD under the sink. The roto machine pulled back a small piece of torn up cloth and threads. Tenant said she ran garbage disposal when clog happened?? Tried to neg. a 30 termination of lease for tenant to move out due to extensive damages and MOLD remed. needed, kitchen needs to be torn out. A contractor said 2-4 base cabinets need replaces and counters torn out and replaced and vinyl flooring, etc. $4500. to $6000. in damages. Tenant fighting back and wants deposit back. Tenant reported me to Denver Health Dept. for MOLD in kitchen, then are suing me in small claims court for $5400.for deposit last months rent plus $2000. for their inconvieniece and moving expenses. Also, they will not let me into property with contractor for bids and I have an access clause with NO limitations.