DSTV - No refunds on wrongfully debited funds

DSTV(Multichoice) STILL owes me 3 month's subscription fees.

Contract cancelled in November 2017. Debit order stopped in November 2017.

Debit order went off in December 2018.

Debit order went off in January 2018. Contract cancelled AGAIN in January 2018. Debit order stopped AGAIN in January 2018.

Debit order went off in February 2018. Contract cancelled AGAIN in February 2018. Debit order stopped AGAIN in February 2018.

Was contacted by Accounts end February 2018. Debit order did not go off for March 2018, finally. Still waiting for the refund of 3 months' subscription fees.

Wonder what the interest is Multichoice is receiving by delaying refunding their clients?