Cut out the jargon and use plain English

I was on an online session on Business Communications and Soft skills when I showed the following to my students and asked them to point out problems and suggest improvements.
Dear Sir,
I am writing to answer your questions about the survey I conducted by telephone on Saturday, September 19. You wanted to know what I asked and who were included in the survey. I questioned a few customers in two groups – Those who are new and those who are long-time customers. The purpose of the survey was to find out why the new customers became our customers and why the long-time customers remain customers. I also wanted to find out what they kn ow about our competition and if the location of the customer made any difference in how long they have been our customer. Other relevant information that I thought would be important is if they like for our representatives to leave voice messages and if our hours are convenient.
Normally I do this since discussing case-studies and real life examples are the best way to learn. Well the letter shown above is obviously an update the writer sent to his boss about a survey he conducted on a Saturday. There are many problems in the letter but lets point out the main ones.

• The Boss obviously had asked this person to report about the survey hence the first two sentences are totally useless.
• The Boss has to read through long sentences loaded with information
• Obviously the person has done some good work but his presentation skill is very bad 

There can be many improvements but here is one:
Dear Sir,
I conducted a telephonic survey on Saturday, September 19. During the survey I called NEw customers as well as Long-time customers. The data that was collected are -

1. Reasons customers choose to do business with us
2. How we rank against our customers
3. Whether our hours of operation and location are convenient
4. Customer's preferred method of contact

-->>I hope you can see the difference. Communication is very important today and it is looked at as the single most important SKILL for career growth.