Tenants Ghosting at End of Lease

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I have a lease expiring at the end of January. The tenants have paid for neither December nor January. They have ceased communication, even when I attempt to discuss utility transfers. I am under the assumption that they will not be paying me another penny at this point. Is it worth pursuing via the court or should I simply cut my losses? 

For reference, the property is in Pennsylvania and it can take months to bring any real action or evict a tenant. Even if I was awarded a judgement, collecting, particularly when they will very much be unlikely to provide their new address, is a whole other matter entirely.

As a follow-up question: Will I be liable for what I am all but certain are unpaid utilities?

Any advice is greatly appreciated.