Water will flow into the pump but very little.
Was it clear... or... muddy?
I know what the repair guy was trying to do, but I don't thing that would have been my first action. I would have tried a snake first beening gentle but firm in poking it down the pipe. Atleast get an idea about where the blockage is. I would have snaked for a long time before trying the acid.
But since the pipe is full of Muriatic Acid now, I would wait for acouple of days to see what happens. I wouldn't try snaking the line with the Muriatic Acid in for awhile. If you are going to snake out the line, remember safety first. That stuff is not nice.
You might have a dead something in the line, so it will take the Muriatic Acid awhile it take care of it. If you do start snaking the line, try and judge about where the blockage is and try and knock it out the shortest distance.
Not sure what else to tell you or what equiptment you have to pump the line out. If you can hook the old pump back up and try and get some of the acid out before you work on it. Maybe calling in Roto-Rooter might help. Compressed air might work; going from the pump end of the line towards the the skimmer. Trouble is, the repair man tried and if he was a good pool repairman, I think you really have something stuck in the pipe that's not going to be easy to take care of.
Just watch out for the Muriatic Acid and your eyes.