whats my next step

The answer depends on the amount of money at issue. If the amount is $6,000 or less, you can file in small claims court in Ohio and you do not need to hire an attorney (though you can if you choose). Small claims court is similar to Judge Judy or other shows like that where each side is able to present its case and evidence, and the judge can ask questions to arrive at a verdict. 

Assuming that HighMark is a corporate entity of some sort (LLC, Corporation, etc.), corporate entities are not entitled to represent themselves in any courts of a higher jurisdiction than small claims (municipal, county, or common pleas courts). If your amount owed (and lien amount) is higher than $6,000, you will need to hire an attorney to proceed. 

Hiring an attorney to pursue a case like this is fairly straightforward, at least initially. You will want to be able to prove your case, and anticipate any counterclaims or defenses. In this case, the contract you signed with the homeowner will play a very important role, since this case revolves around work, your company's right to repair the work, and the scope of work to be performed under the contract. Your attorney should look through your documents, including the contract, communications with the homeowner, and any other documents that you think prove your case. After that, the attorney will be able to provide you with an outlook for the case.