Meta has stopped accepting cards from another issuer. This week, some advertisers paying for @Meta Ads with cards from neobank @slashapp lost access to their ad accounts: Meta stopped accepting part of Slash's credit BINs. Slash confirmed the incident in a message to clients and says 95% of affected users are already back up, with a working fix being a debit BIN or paying invoices via ACH. Meta hasn't given a reason. But the scale is notable: according to Slash's CEO, almost 2% of all Meta ads are purchased with Slash cards, and about $4B a year runs through the company's credit cards. The more interesting part: Slash itself says this isn't a one-off but a consequence of changes Meta is rolling out gradually, and expects other providers to be affected too (no issues at other providers spotted so far). That lines up with what we saw in April, when Meta moved large advertisers off cards and onto invoicing and direct debit. The takeaway for fintech is simple: if your card product depends on a single merchant, the risk doesn't live with you - it lives in their policy. And large B2B billing is leaving card rails for direct ones - ACH, debit, and next, stablecoins.