SMS Delays from SMS providers

[CoinJM]

We recently migrated from RC to Zoom.  Same number block bulk ported to Zoom.  Everything seems to work fine, except......Our big hurdle at this point is another provider's SMS messages reaching Zoom DID's anywhere between 90-120 seconds from sending.  Testing a personal cellular to Zoom DID, Zoom client or desktop soft phone Zoom DID to another Zoom DID,  SMS takes seconds.  From the SMS provider to a personal cell phone, seconds.   

We have a ticket opened with the third party provider, and with Zoom, but not much traction in the last two weeks.

To me, it sounds like some type of routing issue.  Its like it bounces around and finally finds a path out.

What would happen if the two providers didnt have a working relationship [contract type]?  Would the SMS just die or timeout?  

Anyone else experience SMS troubles?

[Zenbu]

Our org is also experiencing this. Today was the topper, CTO sms me and a service desk manager, I don't get it until I open my app an HOUR later, and my SD mgr did not get it till 4 hours later