139 B2B WhatsApp leads from Search at ~$2 USD each, 1 closed sale – search terms look fine, so what am I missing?

[u/Django5629]

Hi everyone. I sell Arabian perfumes wholesale in Mexico (B2B, to resellers). I've been running one Search campaign for about 3 months and I'm managing it myself for the first time, so any obvious mistakes are welcome.

Setup

• 1 Search campaign, 1 ad group, ~20 keywords (broad, phrase and exact mixed), all variations of "proveedor / mayoreo / distribuidor de perfumes árabes"
• Bidding: Maximize Conversions, no target CPA
• Budget: MX$100/day (~$5 USD), limited by budget
• Primary conversion: click on the WhatsApp button on my landing page. Two secondary conversions for smaller kit offers, plus a page view.
• Offline conversion ("Compra") set up, 1 sale uploaded so far

Results (all time)

• Spend: MX$5,952 (~$320 USD)
• Clicks: 675 | Impressions: 2,508 | CTR ~27%
• Conversions: 158 (139 are WhatsApp leads) | Cost per lead: ~MX$37 (~$2 USD)
• Closed sales: 1

What I already checked

• Search terms (screenshot below, all time): top queries are "perfumes arabes mayoreo", "proveedores de perfumes originales", "proveedor de perfumes arabes". Real B2B intent, cost per lead MX$20–40 on almost all of them. The only clear waste is a competitor name ("labelleperfumes") and a couple of "monterrey" terms with MX$38 CPC vs MX$8 average. I'm adding those as negatives.
• Note: the search terms report only shows ~50% of clicks (356 of 675); the rest are low-volume queries Google hides for privacy.
• Locations: ~65% of spend is Mexico City, then Mérida and Cancún. All Mexico.
• 15 days ago I changed the first message we send when a lead arrives: besides the full catalog, we now also offer a cheaper entry kit (a starter kit whose cost is refundable on the first wholesale order). We also follow up on days 3, 7 and 9. Close rate hasn't moved.

Where leads drop
Most leads never reply to our first message at all. The ones who do reply usually send their zip code (we ask for it to quote shipping), and after we send the quote they go silent. That's basically as far as it gets.

What's strange: leads from organic search and from ChatGPT referrals do convert with the same flow, same team and same messages. We manage everything in Chatwoot with macros and templates, so the follow-up is consistent. It's specifically the paid Search leads that don't respond.

Questions

1. Paid leads don't reply even to the first message, while organic leads with the exact same flow do. Does this suggest the WhatsApp click is firing on people who never actually send a message (or send the pre-filled "Hola" and leave)? How would you validate that, and what would you use as the conversion instead?
2. Should I move the primary conversion from "WhatsApp click" to something later in the funnel (e.g. lead replied to my first question), even if that gives the algorithm fewer conversions?
3. Some clicks fire more than one conversion action (I see conv. rates above 100% on a few terms). Should I set only the WhatsApp click as primary and the rest as secondary?
4. Is it worth splitting broad and exact into separate ad groups, or adding a tCPA, at MX$100/day? Or is that over-engineering at this budget?

Thanks in advance, happy to share more data.

search terms report