Longtime lurker, first thread post so I'll try to get it right; not too longwinded but not drip feeding.
I've been a subscriber to The Times home delivery service for over a year now. Every so often my newspaper does not turn up (particularly on Sundays). I ring up to complain and usually spend over 15 mins on the phone listening to different options, piped music etc before being told I'll be given a refund in next month's direct debit.
Earlier this year a nice lady knocked on my door one Sunday afternoon with my newspaper. It turns out she lives in a road with a similar name to mine (eg. I live at 4 Privet Drive while she lives at 4 Privet Close) and said her downstairs neighbour keeps getting my newspapers. This happens a couple of times again so I duly phone up the Times, inform them and they assure me it won't happen again.
Fast forward to 17th March and once again my Sunday Times is not delivered but I get this email:
(sic) "....can you please go and collect the papers as I have been informed that they are disabled and can not bring it to you, the newspapers will be in the veranda waiting for you.
I have told the delivery team to make sure that you will get the newspapers, I am sorry for this inconvience and it will be sorted out for you as soon as possible."
I replied telling them it was not my job to rectify their mistakes and that they had a cheek asking me to collect it ? I did however send my son round to collect it.
They replied with:
"Please accept our sincere apologies for the issues surrounding the delivery of your Sunday Times recently.
We have applied 3 days of credit to your account.
More importantly, we have escalated this issue and are confident that the Sunday papers should now be delivered to the correct address." 
Last Sunday again the paper did not turn up so I emailed them to advise. Monday the paper did not turn up again and I received a phone call from a manager, let's call him 'Dave', asking me to go and collect my paper from disabled lady at 4 Privet Close. I asked him did he have record of the email I sent yesterday to which he said he did not. I told him this was the last straw and I wished to cancel my subscription. This was a very longwinded process being passed to two different departments and eventually speaking to 'Jo' who proceeded to entice me to stay with them by offering me 3 months subscription at half price etc. Told him it was of not use to me even if it was free as they could not deliver reliably. I'm paid up to 8th May.
Anyway 'Dave', the manager assured me it would be sorted. Guess what I did not get today. Yep, no Sunday Times! I spent 25 mins on the phone speaking to 'Greg' who offered me a credit to which I laughed and said no use as I've already cancelled! I told him where the paper would be and asked what were they going to do about it? He couldn't answer so I was really mean and said to him did he want on his conscience a disabled lady not to be able to get out of her house as his papers were blocking her porch? I did not shout or swear at him (very restrained of me I think) but I was mean to him and got off the phone and was very grumpy with DH.
Told DH I was going to speak to someone senior tomorrow and write a stroppy letter. He said "don't waste your time, post on Mumsnet and those stroppy women will sort it for you!" V wise man my DH. 
So if you've managed to get to the end of this very long winded post what would your next step be and should I feel guilty at being mean to 'Greg'"