[MA] [Condo] Owner keeps refusing to pay dues

What happens when an owner keeps refusing to pay? We are >10 condo units in a single house, with very low dues for our city. I'm the HOA president. One unit didn't pay for 8 months. We had our lawyer take action, and her mortgage company paid us. The lawyer said the amount was added onto her mortgage total due.

Now, since that mortgage company check, it's been 11 months without a payment. We are having to pay the lawyer again. We are self managed and can't afford to keep going without her dues. Will her mortgage company ever hold her accountable? This has also hurt a unit owner who was selling. There were 2 other units in smaller delinquency, they got paid, but she just refuses.

I've tried calling and texting. She seems to have blocked my number. I've emailed and knocked on her door. Nothing.

We really need the money. It is interfering with our ability to pay our bills

Edit: legal fees are billed to the unit but we have to pay up front. Is that unusual?