How a Warsaw car service cut its cost per phone call by almost half
The Google Ads dashboard was all green, reports showed hundreds of "conversions" in the form of clicks on the "book a visit" button. At the front desk, meanwhile, silence — the phone wasn't ringing and the mechanics were waiting for jobs. This case study shows how offline conversions and a close partnership with the client made it possible to tell a real phone call from an empty click — and drastically lower the cost of acquiring a customer.
The results the front desk could hear
Cost of a real phone call
Down from 100.58 PLN (Jan–Feb 2025) to 51.64 PLN (May–Jun 2026).
Premium-car segment
Cost of a unique call in Porsche/BMW/Mercedes campaigns fell from 368.76 PLN to 62.39 PLN.
The scale at which the problem was invisible
At these budgets, standard Google Ads reports showed nothing but success — while the phone stayed silent.
Green tables vs. silence at the front desk
The ad budgets of a Warsaw car service were growing — from 2,000 to over a dozen thousand PLN a month — and the Google Ads dashboard reported a rising number of conversions. The system, however, counted every click on "book a visit" as a success, regardless of whether it turned into a real phone call. No one knew how many of those clicks actually reached the front desk. The question was simple: if the dashboard shows nothing but success, why is the phone silent?
Offline conversions and partnership with the client
A strategy built on two pillars: call tracking that connected clicks to real phone calls, and a close partnership with the client in analyzing the results.
Pillar 1: Offline conversions and call tracking
We assigned a separate virtual phone number, based on UTM parameters, to every service on the site. This let us attribute every call to a specific campaign, ad group, and even a specific landing page — instead of an anonymous form click.
Pillar 2: Partnership with the client in analyzing calls
The service owner actively supported building the new landing pages and analyzed the virtual switchboard reports. Connecting ad clicks to actual phone calls and workshop revenue let us pinpoint the campaigns (including automated Performance Max) that generated "empty" traffic and spam — and cut those sources off immediately.
Creative from the Premium campaign
A campaign for Porsche air-conditioning service — one of the premium segments covered by call tracking.
Numbers, not generalities
| Period | Average cost per call |
|---|---|
| Jan–Feb 2025 (baseline) | 100.58 PLN |
| May–Jun 2026 | 51.64 PLN |
A 48.6% drop thanks to eliminating the "empty" traffic and spam pinpointed by offline conversions.
| Period | Cost per unique call |
|---|---|
| Mar–Apr 2026 (campaign start) | 368.76 PLN |
| After 2 months of optimization | 62.39 PLN |
Fast feedback from the client (call reports) shortened reaction time from months to weeks.
Three lessons from the call-tracking rollout
- 01
A button click is not the same as a completed phone call
Without offline conversions you optimize the wrong signal — the dashboard can show nothing but success while the phone stays silent.
- 02
Performance Max can generate "successes" that are really empty traffic
Without verification outside the Google Ads panel it's hard to tell a real conversion from spam or an accidental click.
- 03
Fast client feedback cuts reaction time from months to weeks
In the premium segment, it was the speed of reacting to call reports that made the 83% cost difference.
Do your ad reports show nothing but success while the phone stays silent?
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