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 (phone_number VARCHAR, customer_id VARCHAR)
TABLE: CREATE TABLE complaints (customer_id VARCHAR, date_complaint_raised VARCHAR)

### Question ###
What is the phone number of the customer who has filed the most recent complaint?

### Accurate SQL ###

SELECT t1.phone_number FROM customers AS t1 JOIN complaints AS t2 ON t1.customer_id = t2.customer_id ORDER BY t2.date_complaint_raised DESC LIMIT 1