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Coordination of benefits denial: what it means and the letter to send

Editorial note (remove before publishing)

The build brief for this page calls for Sam's own first-person coordination-of-benefits story. No transcript of that real account exists in this codebase, so this page ships as a factual explainer instead of a fabricated personal narrative. Replace this note and the “What happened to me” section below with the real story before this page goes live — that first-person account is the highest-converting piece of content in the whole plan.

When you have two health insurance plans — for example, coverage through your own employer plus a spouse's plan — your insurers are supposed to coordinate benefits: one is primary, one is secondary, and together they cover your claim according to a coordination-of-benefits (COB) rule set. When that coordination fails — often because the hospital billed only one insurer, or because the COB paperwork on file is outdated — the claim can be denied or only partially paid, and the hospital bills you the full charge instead of following through with the secondary insurer.

What happened to me

[Placeholder — replace with the founder's real, first-person account: which two plans were involved, what the hospital billed, what the COB failure looked like on the EOB, and what happened after the dispute letter was sent.]

How to fix a COB failure

  1. Call both insurers and confirm which is primary and which is secondary on the date of service.
  2. Ask the secondary insurer to reprocess the claim with correct COB information.
  3. Send the hospital a formal letter citing your ERISA § 503 right to claim review (29 CFR § 2560.503-1) and request they hold collection activity while the secondary claim is reprocessed.

BillMender's free checker flags EOB-vs-bill mismatches automatically and drafts this letter for you.

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BillMender is a document-preparation tool, not a law firm, and does not provide legal advice. We don't guarantee any outcome or dollar amount. Estimates are based on public reference pricing, not your hospital's actual contract rates.