[mattfrn]

your bill onpage 3 should be as follows
line rental =£9.50 (or whatever)
any bb or talkplan
then there should be a breakdown of calls ie:
ntl to ntl
local calls
national call
international calls
all other direct dialled


there will then follow a breakdown of each ie;
ntl to ntl calls (all calls over 20p will be shown{it might be different in different regions} and then all other direct dialled calls the amount and cost

where abouts are the calls under??
what dates are they?
if it was before the date the talk 24 was added thats your answer
if the calls are not covered another poss reason
if the calls go over an hour another poss reason
or the last one is when the csr added the charge he /she forgot to change the tariff so the calls would be billed as normal

hope this helps