Well, I am new to the canning business and just realized that I messed
up my plum jelly. I followed the directions, but read them wrong. I
used the recipe below. Can I fix this or just use it as a syrup? Now
that I know what I did wrong (through a bit of internet research and a
light bulb moment), I can make more the right way.

Recipe from Ball Liquid Pectin Package:

Plum
7, 8 oz jars

Preperation of fruit
Pit and finely chop (do not peel). Place in saucepan; add 1 1/2 cups
water. Bring to boil. Reduce heat; cover and simmer 10 minutes.

Ingredients (in addition to 1 pouch Ball Fruit Jell Liquid Pectin
unless otherwise listed)
4 cups prepared plum juice (6 lbs.)
6 1/2 cups sugar

Now, where I messed up is that I read this recipe wrong. When I read
the 4 cups prepared plum juice I thought in addition to the plums I had
boiled. So, effectively I had double the amount of juice I needed.
Can I fix this now? I already tried to re-make it using 4 tbsp lemon
juice, 1 1/2 cups sugar and 4 tbsp lemon juice. That doesn't seem to
have worked either

Please help! At least I know what not to do next time!