Refund me SARS

I owed them R1658,4 they detucted from my old mutual two-pot system, then again from my GEPF two-pot money the balance was settled, they said I owe R5750 ,they deducted R2500 last month from my paye, nd again this month they do not want to refund me I've been calling them almost every day I do not know why they still deducting but my balance has been settled.nd they do not want to cancel the R2500 debit order