Letter to my manager

sir

I wish to write a letter to my manager asking informing him about an issue we are facing in our city. FYI, my office is shifted to a new area . However, our head office is sending the courier to the old address,. Hence, we face a lot of issues with the courier office.so I want to write the following letter. Pl. let me know if any problems with the grammar and sentence formation of the following letter.

Please help me

LETTER

Dear Sir

The address issue has been disturbing our center again and again. The courier office is continuously messing up on account of old address and as a result a lot of problems arise now. Sir, We are not responsible or liable for any issues in future if this address problems continuous.