Please correct me if I'm wrong but from what i have read the 3 main causes for excessive wear/ failures on the follower are
A revision 'a' cam that is worn where the uneven surface will literally eat away at the follower.
Uprated HPFP that put more pressure on the cam and follower
High revs which put more pressure on the cam and follower
Correct on all 3... well maybe the first 2 unless the rev limiter has been raised then 3
As an engine builder for 7 years this is my take on the fueling issues and fuel pump wear.
A worn cam lobe will give you less "stroke" to start with and putting a new follower against the worn lobe will not last as the surface hardness has gone from the lobe and will eat the new follower very quickly. I think some of the fueling issues on mapped engines will show up when the stroke of the cam is starting to diminish resulting in less fuel delivery, So the first port of call is to fit a HPFP this puts more force on the already worn surfaces and will in the end wipe the lot out just has the OP has found out.
I'm afraid if your follower has worn then the lobe is to... Eventually a new cam shaft and follower will be needed to be fitted at the same time.... The roller follower kit looks like it would be the way to go... very nice.
We were always told it is not good practice to put a new follower against an old cam shaft... Well that's my take on it anyway