Telephone operator starts with good old African country (4)
I believe the answer is:
togo
'african country' is the definition.
(country in Africa)
'telephone operator starts with good old' is the wordplay.
'starts with' suggests taking the first letters (I've seen 'start with' mean this).
'good' becomes 'g' (abbreviation).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
The initial letters of 'telephone operator' is 'to'.
'to'+'g'+'o'='TOGO'
(Other definitions for togo that I've seen before include "territory of some West Africans" , "Remaining united" , "African country E. of Ghana" , "W African republic" , "W African country" .)