You are certainly due refund of points since you opted not to take the later alternate transport offered by WN. However, there are no regulations that require they pay for a rental car you booked on your own (even if cancellation was their fault). You can try asking, but ultimately they are not required to give you anything under the law or their Contract of Carriage. They might be still in a generous mood from the massive cancellations a few weeks ago when they opted to reimburse people's reasonable expenses due to the significant negative publicity.