Let us do full analysis of IELTS writing task 1 submitted by a student.
Question:

You bought an equipment from the market and when you reached home, you found that it did not work. Write a letter to the shopkeeper and in your letter, write

• Say why you are writing
• What went wrong the product your purchased
• What you want to do now

Candidate’s Response:
Dear Sir,

I regret to inform that I purchased LG microwave in your shop last week. Moreover, it is white in colour and its weight 20 kg approximately.

In addition to this, I was happy when I brought an electronic equipment because I got 20% off from your site. Unfortunately, within two days electronic light inside the micro wave have switched off. When I pluge insert in the socket and switch on after that processing inside the microwave is started. However, light is not visible inside while processing. So, I am not satisfy with with product.

Furthermore, I gave this product in your shop for repair yesterday. Your workers said me we can not repaired well. On the other hand, now it is not working all though, light was not on inside it but it was working well. So, please give me some solution to tackle this problem. I hope you will give some suggestion for this product.

I look forward to receiving your reply.

Yours faithfully,

Ratan

Now we will do analyse of the above IELTS writing task 1 response as follows:

Para 1
Strength:
Purpose of letter is attempted along with details of the product.
Corrected Erroneous Statement:

I regret to inform that the LG microwave that I had purchased in your shop last week has stopped working. The purchased microwave is white in colour and it’s weight is 20 kg approximately.

Para 2
Strength:
Problem with the product is well explained below.
Corrected Erroneous Statement:

After shopping from your store, I was happy to brought this electronic equipment because I got it at less price of 20% off from your site. Unfortunately, within two days, electronic light inside the micro wave have switched off. When I insert its plug in the socket and switch on after that processing inside the microwave is started. However, light is not visible from inside while processing. So, I am not satisfied with this product.

Para 3
Strength:
Sentence connectors (furthermore, on the other hand) are used and third part of the question is explained well.
Corrected Erroneous Statement:

“Your workers said that they could not repair it well. Moreover, it is not working at all now as the light is not visible in the indicator button”
Expected Band Score: Band 7

The candidate has written without errors of grammar and tense. However, there are mistakes related to punctuation and others.