We apologize as, due to our company's staff transfer, we have been unable to visit you. We have generated a new schedule to visit with our members. We would like to know if you are still able and willing to accommodate our request. Please let us know your availability and send us a letter of invitation when you are able to speak with us. I am assuming this is for a business, so I reworded it more professionally, although it is difficult because I don't know exactly what the business is about. There were a few common mistakes such as starting a sentence with because. Also, it is much more professional when you do not use conjugations in formal writing, even in an e-mail to a coworker. Hope this helps!

There is a slight difference between impede and prevent. To impede would be to stop something that is already in progress, or nearly in progress, it is more like to interfere than to prevent. To prevent means to stop something that has not happened yet. Example: The traffic jam impeded my arrival. I had my dog vaccinated to prevent disease. They are similar, generally you may use prevent to replace impede, but impede does not usually replace prevent.