Let's talk Tenna and Spamton's relationship and the fact Tenna chose the phone instead of going after Spamton.
I'm a firm believer that they were more than partners and they had a very loving relationship. This is canon in my opinion. Neither of them can go two minutes without saying something about the other, they live rent free in each other's heads. Yes in present day they talk shit but they're both hurting by perceived abandonment by the other. There's plenty of folks out there I think do a wonderful analysis of the two's relationship that put it into better words than I could, so I'm not going to dive too deep into that aspect of this.
So if they were so loving, why did Tenna go after the phone instead of Spamton? Well there's two possible reasons for this.
One, Tenna is shown to be pretty bad at reading the room. He's constantly bringing up memories of the family together, when the stuff like the divorce or Dess not being there probably isn't something Kris would remember fondly. In addition to this, the deal he and Spamton are making is going swell. He has no reason to suspect something is wrong. Yes Mike warned him but Spamton -chose- to sign regardless. Whatever it is, they can deal with it together. So when Spamton goes running out, it doesn't immediately dawn on to him something could be wrong. Maybe he needed to attend to something important in the moment and since they were signing the deal right there, may as well talk to the benefactor himself.
Another option, and one I personally feel is more likely, is Tenna was aware the way Spamton ran out wasn't right. But he still didn't think Spamton would just -leave-. Spamton spent a lot of time at the studio, he could go speak to him soon, but what exactly did the benefactor say to him to make him run out that way? Whatever it was hurt Spamton, and I'm sure we know about partners who give the person on the other end of a phone call a piece of their mind if they see their significant other fall apart at whatever was said to them.
But wait, this doesn't really line up with what Tenna said in the third round of the Mantle game. He makes it sound like he strictly had the benefactor on the mind.
Guilt is a wild thing on the psyche. We know Tenna feels immense guilt over Spamton leaving from the Chapter 5 scene teased in the newsletter. He was warned about the contract, pushed for it anyway, and anything could have happened to Spamton due to his own, perceived selfish, desires. That would eat any caring partner up. With that kind of guilt, it can be easy to be made to believe things didn't exactly happen the way they did to cope.
Spamton ran out because something better came along, he's fine he's just living it up without you. You -wanted- to reap the benefits he had, that's why you went to the phone first. You two were business partners, nothing more.
Lies made to cope with feeling both abandoned by the one he loved and the fear that something terrible couldve happened and he perceived it as his fault.