Revocation of cancellation of registration allowed with returns filed and tax paid, final deadline applies and no further extension. A special procedure allows registered persons whose registrations were cancelled under clause (b) or (c) of section 29 on or before 31 December 2022, and who failed to apply within section 30's time limit, to apply for revocation up to 30 June 2023 only after furnishing all returns due up to the effective date of cancellation and paying tax, interest, penalty and late fee; no further extension is available and appeal rejections for delay under section 107 are included.