Hello, i am having trouble in solving a case study on business law, can you provide a detail explanation.

Here is the case:

Billy is keen to start his own business selling frozen pizza on-line using the internet.

He decides to advertise his pizza by using the daily newspapers.In the advertisement he states as follows :-

High Quality Frozen Pizzas available for sale

We accept orders on-line at www.frozen-pizza.com.

Place your order now and receive a 50% discount off

the original price of $20.00 per packet.

Terms and conditions apply.

Esther is a canteen operator who used to make her own pizza using the basic ingredients.However, when she saw how cheap the frozen pizza was being sold, she decided to place orders for these.

She goes to Billy's website and places an order for 200 packets.The delivery is to be made within one week as Esther has a big catering project.However, she fails to read the terms and conditions column before placing the order.

Unknown to Esther, Billy has reserved the right to accept or reject any order above 100 packets.This limit was placed by Billy as he was concerned about the sharp increase in the price of flour given the current surge in the price of such commodities, as it would than make his business less profitable.

Meanwhile, the on-line ordering idea proves to be a failure as not many people use the internet to place orders.As a result, Billy reverts to his traditional mode of taking orders over the phone and he abandons the on-line project.

Esther on the other hand fails to receive her order of 200 packets.As a result, she is unable to cater for her customer at a major corporate function.Her customer threatens to sue her.

Advise Esther and Billy in solving this case? What is each party's rights and obligation? Can Esther's customer sue her and can Esther sue Billy?

Thanks