A sofer was hired to write a Torah. Due to health issues (various bad pains) he had to stop part way through. Another sofer was hired. The original sofer ended up not writing 1-1/2 columns in the middle and due to not being able to get to the mikva with regularity left space to fill in 125 Shaimos. (I believe the sofer could have filled in the Shaimos before quitting by doing it over the course of a number of weeks as he’d already been writing for weeks with considerable pain and had he filled them in in short spurts over some weeks he wouldn’t have suffered much. Anyways, when I got the yerios and saw that he didn’t fill them in, he told me that he’d already gotten rid of his table, etc. He was going to pay for all the costs to complete what he didn’t.
Months later the sofer contacted me and asked if I knew where he could get a 2nd hand writing table as he wanted to try to do a little writing. I told him that if that’s the case, the yerios he wrote still need the Shaimos filled in, some letters/words filled in after being checked and erased/prepared for rewriting and the 1-1/2 columns written. It’s a very big aesthetic bedieved (maybe menumar?) to have multiple Shaimos etc, and the 1-1/2 columns look different. If he was feeling up to doing a little writing and investing 500-1000nis in a table, I offered him to use my spare table for free and start off getting back into writing by finishing what he started and only stopped due to being an anoos, which he may no longer be. In the meantime, he’s not responded to my multiple messages. I don’t think he has the right to start writing some mezuzahs to test the waters when he can just as easily gradually test the waters completing what he didn’t.
It is correct that he should finish your work if he can work since it is considered a loss to have two sofrim write a sefer Torah (See Ramo siman333)-it is called menumar as you write