Useless MTN blocks all 0800 numbers

MTN blocks all 0800 numbers on my contract phone with top up - I have escalated this complaint now 4 times over the last 4 weeks - Zero action - that means I can not call any RSA Government department (eg SARS) - and the block is for all MTN phones in my family that are contract phones with top up airtime - MTN you are useless sort out this mess and inform your help centre that always blame it on the phone where this is CLEARLY an MTN Network issue!!!