No, that is not quite correct since it is missing the important article “a" and "customer" is misspelled. Say instead: “I am a loyal customer of yours.” ← Notice the addition of the “a” before the word “loyal.” Though it is grammatically correct with the added article, it still does not feel completely natural to say. Here are few suggestions for what you might want to say instead: “I am going to be a loyal customer of yours.” “I will be a loyal customer of yours.” ← What I would probably say. Notice that both of my sentences are in the future, while your sentence is in the present. It is more common to use the future tense in this circumstance since you are trying to convey to the company that you will do further business with them in the future. I hope this helps. :) If you would like to practice speaking, please feel free to look at my teaching profile and class offerings. Kristin https://www.italki.com/kagcafe

Hi ila, Adding to Kristin's answer, we also say "I'm a regular." or "I'm a regular customer of yours." to mean the same thing.

Yes