This has happened a couple of times to me over the years.
You can either...
A, Bodge it up with a bit of pipe tightly fitting inbetween the 2 broken bits...It does work fine.
B, Same as above but with a pice of metal tube with the same diameter as the hole, Also works fine but more of a permanent fix than above.
C, Replace the cap end...£36-odd last time I bought one.