I am an engineering student on work placement. I am on a £20-a-month mobile phone plan with Three, entitling me to an internet allowance capped at 2GB. I moved house in April, forcing me to rely on the mobile as a wireless tether for wifi connections on my computer. But without me instructing it to do so, my phone shared the internet connection provided by my network operator with my computer.

Consequently, Three sent me two messages within 15 minutes - the first stating that I was close to my limit and the second that I had exceeded my limit and been charged £32 for this. I was appalled at having to pay £32 for 15 minutes of use, so I called Three the next day. Three merely said the charges were in line with the payment plan.

Eventually, they agreed to bring forward my internet allowances for the next month by three days and waive half the excess internet charges levied.

But this did not happen and I was charged again for exceeding my allowance. Now Three is chasing me for payment of £102. I don't understand how it can justify these charges when the internet allowance element of my contract costs only £5 a month. AK

Just after you contacted us, you left your handset on a train and were being chased for a bill of over £100 for a phone that you could no longer use.

At our suggestion, you immediately informed Three to put a stop on any calls being made from the handset. You tell us that the matter of the outstanding bill has now been satisfactorily resolved by Three: it apparently told you that it was waiving any charges in this instance.

In April, I asked TalkTalk to upgrade my account to TalkTalk Plus, taking advantage of a special offer. I was told that I would benefit from a six-month half-price offer for renewing my contract in addition to the upgrade. I was to hear from TalkTalk within a week with confirmation. But when I heard nothing after a week I contacted TalkTalk again, to find it had no record of my previous order. I then re-ordered, but again heard nothing.

At the end of April I was told "there had been a delay in activation of the contract renewal". On May 13, I received a call from TalkTalk to advise that my account could not be upgraded as "changes were being made to the account".

I complained to the company's chief executive on 27 May and received a reply saying that the matter had been escalated on 13 May and that I should wait 28 days for it to be resolved. When this did not happen, I wrote another letter to the chief executive and on 12 July received a reply asking for my name, address and account details. How hard can it be to upgrade? JC

TalkTalk apologises for your difficulties, which were caused by what it calls a "systems error". Your account has now been upgraded to TalkTalk Plus.

My daughter has just left university. While a student she had access to the internet and TV from Virgin Media. She started the contract in September 2009, renewed it in September 2010 for a year - and cancelled it when she left university on June 6 this year. Virgin now demands a £44.99 cancellation fee. This seems excessive.

We have been unsuccessful in our attempts to talk to Virgin Media at its stores, which say they cannot help. When we did speak to them on the phone we were promised a new bill to specify the charges, but this did not arrive. BC

Virgin Media tells us the £44.99 is the account balance comprising the last service bill, which was not paid, plus a contract cancellation fee, as laid down in the contract. The company argues the bill is correct. A spokesman adds that contract termination fees "are regulated by Ofcom and are standard across all contract-based continuous service providers".

We checked this with Ofcom, which advised us that Virgin Media - along with BT and TalkTalk - agreed to reduce its contract termination fees last year. Virgin Media's lower fees were adopted in October and November. Termination charges for its common broadband and phone package that had been £29.99 were reduced to a more reasonable £4.63.

With assistance from Questions of Cash (April 9, 2011), I obtained a refund from Ryanair for costs incurred as a result of a flight cancellation caused by the volcanic ash.

I have eventually obtained a statement explaining which parts of my claim had been accepted. It turns out that Ryanair rejected approximately €100 of our claim in respect of two meals on the basis that we could only supply credit card vouchers rather than receipts. Yet we have demonstrated that we incurred the expenditure in two restaurants. RR

Ryanair spokesman Stephen McNamara responds: "The EU261 guidelines are quite clear in requiring 'receipts' and not simply credit card payment slips, which are not receipts. Since we have already refunded €796 of this passenger's €980 claim, with just €94.20 disallowed for non-receipts, we have more than met our obligations."