Retention Call centre forever unavailable

I have been calling MTN 808 call centre with an account query, I get through to first general call center, BUT as soon as I am transferred to the Retention call centre, my calls are NEVER answered, I get the annoying music for 30mins plus until I give up, this has been going on for 6 working days, So today 8th November I tried going into their walk-in centres, guess what?systems are down, I am gatvol, and to think I was willing to upgrade my contract, but after this terrible service, they have definitely lost a loyal postpaid client of 10 years.