'Due' isn't a verb so it doesn't have a past tense.
The past tense of 'spell' is 'spelled'. 'Spelt' is also used in British English.
have in past tense is had
The past tense of have is had.
The past tense is had.
You spell the past tense of settle like this: Settled
spelt per American Heritage Dictionary "alternate past tense and past participle of spell".
The past tense is traveled.
The past tense is 'told'.
The past tense is hoorayed.
The past tense is roped.
The past tense is coasted.
The past tense is benefited.