How to succeed cold calling through main office lines?

I'm fairly new to cold calling

I'm reaching out to Advertising agencies and need to speak with mid-seniors to set up an intro call. We're sourcing our leads from seamless and it's mostly main office lines. It goes to VMs almost 99% of the times. Else receptionist won't let it through etc.

• Any other way to engage with these prospects besides calls.
• Any tool recommendations for cell phones which is not too expensive

Lastly, how to best approach prospects via LI. Here is what I do:

Send a connect request with no notes as that didn't work for me. Followed by a 2 liner with a bit of text around the pain point and a ask?

Would love your guys input