How to formally say : "I am yyy calling from xxx company, how can I help you ?"
Say 你好 (Hello) first

It sounds more formal to state what company you are from before stating your name. &quot;我是 xxx 公司的客服 yyy&quot; or &quot;我是 xxx 公司的客服, 我的名字是 yyy&quot;

Since you are speaking with the customer on the phone, &quot;打过来的&quot; or &quot;给您打电话了&quot; is redundant. Just like you wouldn't need to say &quot;I am talking to you in person&quot; if you are face to face with the customer.

Either 请问有什么可以帮助您 or 请问怎么能帮助您 is fine for &quot;how may I help you?&quot;

add final particle (呢) to soften tone, express keenness

Say &quot;请问有什么我可以帮助您呢?&quot;  instead of &quot;请问有什么可以帮助您呢?&quot; to stress 'it is I who will help you'



&quot;你好, 我是 xxx 公司的客服, 我的名字是 yyy, 请问有什么我可以帮助您呢?&quot;
or
&quot;你好, 我是 xxx 公司的客服 yyy, 请问有什么我可以帮助您呢?&quot;