No tax certificate for retirement annuity

I have a retirement annuity premium that is supposed to be taken off my account on the last day of the tax year to enable me to claim the annuity deduction in that tax year. Although I made sure I had sufficient funds in my account, the deduction was only made by Old Mutual a few days after the end of the tax year with the result that they have not been able to give me my tax certificate for the 2015 tax year. I will thus have to wait a miniumim of eighteen months after payment of the annuity premium to obtain the tax benefit and have now underpaid provisional tax as a result of estimating my tax based on this premium going through which could lead to an interest charge being raised by SARS on underestimation of provisional tax.