Problem solving letter

A few weeks ago I bought a 1000GB hard drive from your store in New Bridge street. I was really happy to arrange all my work files with this HD until yesterday. Yesterday morning I started to use using work files from the HD, but it took a really long time to read and it was stuck froze in the end. I tried turning my computer on and off my computer several times, but it did not work. I could not open the files at all. This is why I am writing to you.
 
I have a lot of work which should have been finished by today. Also, all of my meeting appointment files was in were on that HD. I could not see the places and times, so I had to cancel them out my meetings. Yesterday afternoon I called your customer service, but they explained that I would have to wait at least ten working days before they would help me.
 
I can’t deal with all my urgent matters without this ad HD, so I could not wait and I cannot wait such a long time to fix it. It is still under guarantee. I hope you can assign a staff who is skilled at solving this kind of technical problem as soon as possible.
I am looking forward to hearing from you soon.

Your faithfully Regards,
Ann Law

Froze = when computers get stuck we usually say they 'froze' in English.

HD = should probably be capitalized.

Your faithfully = is probably too polite for a letter like this. "Regards" is a little more serious and business like.