Too small travel allowance - different to actual costs

I have a R 2 500 travel allowance (R 30 000 a year) provided to me. But for 2015 I calculated my true travel costs (travel allowance) and it should have been R 70 000 a year.

Travel allowance on my IRP5 R 30 000
Travel allowance calculated by SARS tables R 70 000

Can I claim the R 70 000 tax deductible or am I limited to R 30 000 tax deductible?

No you will be limited to the travel allowance received unfortunately as that was the financial benefit you received.