Having lived with cattle all my life and knowing a number of cattle vets, most of them good, what happened to you just happens.
Have had the vet out to pull a calf and when he got here he discovered the endgate of his truck opened and he had lost his calf puller somewhere along the road; he had to go back to town and get another one....he was just a beginning vet and pulled the calf, the pull was so hard the calf was brain damaged and never stood up nor even held his head up; he shoulda been a section; could have saved him but the vet did the best he could, he felt bad was a bad deal.
Vets have come out for chute work and forgot at the clinic their saw for removing horns, or a number of times some vaccination or implants; we sit and wait if they go back and get it or better yet you get to haul those in that need dehorning for example at more expense to us...
probably one of the most upsetting times to me was when a cow had prolapsed her uterus after calving so got the vet out immediately; most times if this is treated quickly the cow will breed back with no problems, and that type of prolapse will never happen to her again; so did everything right, kept her quiet, got the vet out ASAP but he brought along one of his kids who spooked the cow then she tore her uterus that was hanging out and had to have essentially a hysterectomy to stop the bleeding and save her life. She was a very good cow and this saved her life but rendered her a non breeder, good for nothing but the sale barn. The vet didn't even apologize cause to him, I am sure, it was just another cow,we have lots of cows, she had salvage value, and he did not GET IT that her value to our program was much more than just a sale barn cow.
But shit does happen.
We did not complain to the vet, what good would it do? He is a good vet and has also saved animals that we didn't think had a chance either. Life goes on.
Sadly in your case as happens sometimes, everything that could go wrong, goes wrong.
You made a huge error, the vet or most likely his hired help made a huge oversight (mistake) also.
LOL, this reminds me of another story...our son is an attorney and he has a secretary....as he signs papers she has typed, he is putting his signature on those documents....he is essentially at her mercy; if she makes an error, it is his signature that goes on the document, essentially making her errors his responsibility; it drives him crazy. He has caught her in error on occasion, as we are all human, and he is unsure yet how much do you trust another human in affairs in which YOU are the one responsible for the end product??? This is what essentially happened with your situation; we don't know what the consequences were to the person who SHOULD have restocked the suture thread.. Perhaps none, perhaps they had consequences.....I would sure think that it was not the vet that should stock his supplies, they don't around here, in fact during calving the vet sleeps in the truck as the hired help drives him from call to call....