I tried reading other posts to see if has been human error on my part
as to why my vlookup function seems to have reached a limit and/or
returns random values.

I've already checked the field from which the formula should cover
(for instance: A1:A250). I have over 200 rows and will progressively
grow as I continually add more data to throughout the year.

Now, what I'm seeing happen after the 49th row is that it cycles
around or randomly chooses a value completely off from the actual
data.

Take for instance: (search for Name5):C1=(UserDefined)

12 Name1
..
..
..
39 Name 2
..
..
..
48 Name3
49 Name4
50 Name5

The formula I tried: =VLOOKUP(C1,A1:A250,2)

So long as I stretch the formula's search field to cover to the 49th
row, it is all true and correct. 49 is and correct and accordingly,
Name4. But, when I extend the search field to the 50th row, it returns
Name1. If I stretch it to the search 54 rows, it returns Name2.

I also tried other methods such as: (being that column A is the number
column and column B are the names. C1=User Defined for the names)

=INDEX(A1:A250,MATCH(C1,B1:B250)+0

I still get a random value returned to me again.

If I could find out where I'm going wrong from anyone, I would greatly
appreciate it, thanks.