Spend Limit increased without my full knowledge!

I have had my Telkom mobile contract for seven months - and I regret it! Currently, the problem I am facing is that my spend limit was increased to R950 without me being aware. Up and until last month, once I had depleted my 100 free minutes for the month, I would be notified upon reaching my limit. I would then personally increase my spend limit to R100 (sometimes up to R200) for the remainder of the month. Suddenly however, my spend limit has been increased to R950 & NO notification is provided to you until you receive your bill! From paying R500-650 a month at most), I suddenly received a bill for R950!!! I immediately phoned Telkom & was told why my bill was higher than usual. I requested that my spend limit be reduced to R70 as I am not prepared to receive anymore high bill surprises! This however is only effective as of 1 May 2016. I was told the only way to track your costs (above my contract) is to get the Telkom App BUT when trying to register, it is not accepting my cell number! (I was previously a Vodacom customer and did a sim migration to Telkom). How can one track their expenses without being able to monitor the cost of additional calls made? This is not on Telkom!