Call center owners: what ad spend actually gets you clients via LinkedIn/Meta/Google?

Running a call center and trying to win new B2B clients (companies who’ll outsource their calls/CX to us) through paid ads.

If you run or have run a call center / BPO and used LinkedIn, Meta, or Google ads specifically to land clients, I’d really appreciate hearing:

**•**	Which platform worked best for you  
**•**	Roughly what cost-per-lead or monthly budget got you real traction  
**•**	Any ad format that outperformed others

Can’t find any published benchmarks for call centers specifically — everything out there is SaaS/tech data. Looking for real numbers from people who’ve actually done this, not general marketing advice.