Subcontracting electrical jobs, invoicing through Housecall Pro is killing me on delays

Subbing out for a main contractor on a big service panel upgrade, billed $4500 for the 200A upgrade with Square D QO breakers and they paid up front no problem. But when it comes to invoicing the subs like me through Housecall Pro, it's a 45-day wait and I'm sitting on my cash flow. Saw a post on r/electricians about this exact issue with GCs dragging feet on payments.

Same here man, 60 days out on my last sub job.

Hate that wait, ties up everything.

Don't ever sub without a solid contract spelling out payment terms within 30 days or you'll get screwed every time.

GCs are the worst, always finding excuses not to pay us sparks on time.

This the norm or can you negotiate better terms upfront?

Customer called at midnight about a tripped breaker, I showed up in pajamas, billed double.

Square D panels are solid but man, the paperwork after is a nightmare.

We all been there, subs get the short end every damn time.

Insurance companies and GCs teaming up to screw us over, it's everywhere.

PE firms buying up shops and making it worse for everyone.

At least you got paid upfront on that one, I had a GC ghost me for two months lol.