First, determine if you have insurance coverage for claims of defamation. Business liability insurance will often have broad form coverage that includes advertising injury and personal injury coverages that include defamation. If you have insurance, the insurer will pay for the defense of the claim.
If you do not have insurance, you will have to pay for an attorney to defend the company. It is a cost of doing business. Your alternative is to allow the default to stay in place and have a judgment eventually entered against your company. That will likely be far worse than paying an attorney to properly defend the matter.
Attorneys usually will not work for companies for free. Pro bono work is usually reserved for low income individuals with important needs. As a company, you will need to decide if hiring competent counsel is important enough to pay for, or are the alternatives more palatable.
Good luck to you.
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