Turns up, Heather has no heart contacting Old Bob Samuel in Kill? (8)
I believe the answer is:
massacre
'kill?' is the definition.
(I know that massacre is a type of kill)
'turns up heather has no heart' is the wordplay.
'turns' becomes 'mass' (I am not sure about this - if you are sure you should believe this answer much more).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'heather' becomes 'erica' (the plant genus Erica includes heather plants).
'has no heart' says to hollow out the word (remove centre letters).
'erica' with its middle taken out is 'erca'.
'erca' in reverse letter order is 'acre'.
'mass'+'acre'='MASSACRE'
'contacting old bob samuel in' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for massacre that I've seen before include "Slaughter in large numbers" , "Large-scale indiscriminate killing" , "Slaughter, holocaust" , "Slaughter, pogrom" , "The slaughter of many" .)