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 addresses ( address_id number, address_content text, city text, zip_postcode text, state_province_county text, country text, other_address_details text )
TABLE: CREATE TABLE customer_addresses ( customer_id number, address_id number, date_address_from time, address_type text, date_address_to time )
TABLE: CREATE TABLE products ( product_id number, product_details text )
TABLE: CREATE TABLE customer_contact_channels ( customer_id number, channel_code text, active_from_date time, active_to_date time, contact_number text )
TABLE: CREATE TABLE customer_orders ( order_id number, customer_id number, order_status text, order_date time, order_details text )
TABLE: CREATE TABLE customers ( customer_id number, payment_method text, customer_name text, date_became_customer time, other_customer_details text )
TABLE: CREATE TABLE order_items ( order_id number, product_id number, order_quantity text )

### Question ###
What is the payment method of the customer that has purchased the least quantity of items?

### Accurate SQL ###

SELECT t1.payment_method FROM customers AS t1 JOIN customer_orders AS t2 ON t1.customer_id = t2.customer_id JOIN order_items AS t3 ON t2.order_id = t3.order_id GROUP BY t1.customer_name ORDER BY SUM(t3.order_quantity) LIMIT 1