Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE customers ( customer_name VARCHAR, customer_id VARCHAR )
TABLE: CREATE TABLE mailshot_customers ( customer_id VARCHAR )

### Question ###
Show the names of customers who have the most mailshots.

### Accurate SQL ###

SELECT T2.customer_name FROM mailshot_customers AS T1 JOIN customers AS T2 ON T1.customer_id = T2.customer_id GROUP BY T1.customer_id ORDER BY COUNT(*) DESC LIMIT 1