Managing credit rating for small/medium business?

My company was part of a much larger organization until a few years ago. Most of our costs are related to personnel and Intercompany (for our tools used in operations) with the remaining $1m USD of annual expenditures spread across about 50 suppliers.

We have several accounts with D&B but have never monitored them as it is full of incorrect information and tied to old locations (and other former affiliated companies that have nothing to do with ours). We've also learned that there are accounts for us through Equifax, Experian, etc. that require time and recurring monthly subscriptions to 'correct' the information on their sites.

Most of our newer suppliers perform the old school approach of calling our established supplier references that we provide. We've changed names a few times due to ownership and/or rebranding but have always kept the same Tax ID. Some suppliers rely on these 3rd parties and have turned us down recently. Just wondering if there is an easy way to prove that we've been paying our bills for about 15 years on time (some suppliers as high as $300k/year) and improve our rating without having to sign up for each of the various groups and pay multiple monthly fees.