Unfortunately, there is little enough that you can do. Immediately serve a notice of termination for non-payment of rent; the notice period is 28 days. Then apply to PRTB for an order against the tenant - for both possession of the premises and for the rent arrears. It is very slow and the system seems to bend over backwards for tenants, but at the end of the day you will get your order if you are entitled to it. See www.prtb.ie