What would happen if there were no agreement except pay when able?

My company had agreement with supplier that told us not to worry pay as you can. Nothing was signed, no credit forms, no invoices signed or even sent. The company suddenly was bought, new owner calls due all monies immediately. I call to make payment. They tell me just mail or do online no big deal. Next thing we know, lien letters sent to customers, half of which long been paid for and when we contact them they say it was all mistake! Make calls with us half a day, say letter of apology and an explanation will be sent, then next day say no letters will be sent. No agreement was ever made between my company, the new or old supplier, and me. The new owner doesn't know how to spell our name and never once called company or sent letter prior to lien letters, that by the way was accident, then not. My name and word of mouth is my business. They can do this when no one ever signed a thing, homeowner included. I, by all means, am trying to get out of it. We owed over $70,000 at moment with balance of $30,000 I think with the supplier. We were never given invoices until right before lien letters.