Cyber Ltd (Cyber) is a shop that sells and repairs computers. They have recently encountered two contractual difficulties:

Callum needed a new computer and saw one he liked in Cyber's shop. Cyber's assistant said: "We could let you have this computer for 800 if you let us know today". Callum said that he would think about it and asked the assistant for the shop's number so that he could send a message later in the day. However, although Callum sent a text message saying: "Please reserve the computer I saw at 800, Cyber did not receive the text message because they had given the wrong number to Callum. Cyber have now sold the computer to someone else.

On another matter, Cyber placed a notice in their shop window advertising for sale their anti-virus software: "Safety First". It said:

"Buy Safety First today for 50 and get long-lasting protection from all known computer viruses. We are so confident of our product that we will pay 1,000 to any customer who still gets a computer virus after buying and correctly using Safety First."

In response, Phil went into the shop and bought Safety First. Cyber installed it on Phil's laptop computer. Unfortunately however, one week later his laptop computer gets a virus. Phil goes into the shop and claims to be entitled to the 1,000 mentioned in the advert.

Advise Cyber as to whether they have entered into contracts with Callum and Phil.