When is free not so free? Michael Pratt is trying to find out. Last July he called NTL and charged €232 to his Visa for one year's subscription to their service.

After doing this he was pleased to learn that this entitled him to a free extra NTL point in another room and he opted to have it installed in the bedroom. The extra point was duly installed but on receiving the first invoice he was charged €75 for it.

"I queried this, and was told this wasn't for the point, but for the labour involved. I've called them a number of times - however, I'm getting nowhere. If there was a charge for labour, then the extra point wasn't free, he rightly points out. "I was not told of this charge when I called them to get their service. One of the people I've spoken to at NTL told me it wasn't even the right price, that the correct price was in fact €50! Could you please help me as I'm tired of the poor customer service I'm getting. I think the €75 should be credited."

We contacted NTL to find out what had happened. A spokeswoman said that while she could not comment on individual cases it certainly did sound like something was not right in this instance. She expressed concern that our reader had not been able to establish to his satisfaction what the €75 charge was for and suggested our reader contact her directly so she could investigate the matter further.

We have passed on her details to our reader.

The subtleties of quibbling

Jim Harding has been in touch with a couple of quibbles about Tesco's no quibble policy. He was at the till in his local Tesco when he noticed that the price that was scanned for a particular item was different to the price that was marked on the shelf. In the store in question there was "a very large sign" saying that if the price charged at the till was different to the price on the shelf Tesco would waive the charge completely. "They call this their 'no quibble' policy," he writes.

"Anyway I pointed out the discrepancy to the cashier who checked the sign on the shelf and made the correction at the till, charging me the price that was marked on the shelf."

When he asked why he was charged for the item he was told that the cashier did not actually charge the incorrect amount and the the policy applies when the incorrect amount is charged and subsequently paid. "It seems the thing to do is to pay the amount, walk out of the shop and then return to the customer service desk and seek a refund," he writes.

When we contacted Tesco, a spokeswoman confirmed that the cashier had acted in accordance with company policy. "He hadn't been charged the wrong amount. The mistake was rectified before he paid so the no quibble policy did not come into effect," she said.

More recently, Harding was in Tesco and bought two packets of Castelli Light Mozzarella cheese. "A sign on the shelf said 'Castelli Fresh Mozzarella - Buy one get one free'. When I checked the receipt I saw that I was charged for two mozzarellas, so I returned to the customer service desk and pointed out the discrepancy. They investigated the sign and decided that the offer applied to Castelli Original Mozzarella and not the Light version. The total amount of the overcharge was only 69 cent, but 'no quibble' certainly seems to mean something different to Tesco than it does to me."

For its part, Tesco said that such confusion does arise quite a bit with shoppers picking up slightly different products to ones that are on special and then expecting a discount. We were told that special offers and discounts are always clearly marked in an effort to avoid such confusion.

Squeezing every last drop

A reader got in touch after being annoyed by the price of water near her tennis club. "I was due to play a game of tennis at Donnybrook LTC early in the morning and forgot to bring a bottle of water. At 9.30am the clubhouse was shut so I wandered over to the Shell Garage opposite in Brookvale Road to discover the cheapest 500ml bottle was €1.30! Isn't that airport prices rather than convenience shops in garages?" she asks.

Mind your bleeping car key

Martin McDonald from Blackrock in Dublin e-mails to say that while he was in Spain the remote control key for his Ford Focus was stolen. "I have now replaced it with a non-remote-control type from the garage where the car was purchased - Crawfords in Dún Laoghaire," he says. "The total cost was €122.50, made up as follows: labour €73, key €35, Vat €14.58. I find this outrageous and when I said so in the garage it did not help to be told that a replacement key for a Mercedes would cost at least €200." To replace the remote control key would have cost in excess of €200, he adds.

We contacted Crawfords, and a spokesman explained that the labour charge is high because the complicated process of coding the new key to the transponder in the car's ignition takes about an hour.