Night express data being deducted incorrectly

Please can someone help. I am losing my patience with the call centre.

I was allocated 3gig data + 3gig night express on my contract today. The sim is in a router.
At 5:30 i did a update of ±300meg. At 5:45 my pc rebooted iow the session ended?
I went online at ±6:20 and checked my balance and saw the data went off my normal bundle, and not the night express. According to networx monitor I used 268meg before 6h00 and ±70 meg after 6h00
Night express balance is 2.98G and normal is 2.6Gig.

This started about 2 weeks ago. I have never before had any problem with MTN. If a rep can help me I will be very grateful!

Is there perhaps an MTN rep that can look into this for me please?

2018-05-21 05:13:23 mymtn mymtn 44.949MB MTN R 0.00
2018-05-21 05:15:37 mymtn mymtn 584KB MTN R 0.00
2018-05-21 05:53:23 mymtn mymtn 53.132MB MTN R 0.00
2018-05-21 16:52:32 mymtn mymtn 66.268MB MTN R 0.00
2018-05-21 16:56:56 mymtn mymtn 38KB MTN R 0.00
2018-05-22 02:55:56 mymtn mymtn 9.732MB MTN R 0.00
2018-05-22 05:55:44 mymtn mymtn 170.88MB MTN R 0.00

Recurring Night Express Data (Monthly) 0.00 GB 3.00 GB
Expand Adhoc Data Share Recurring Account - GB 2.64 GB

So according to my itemised statement I have only used 66MB of my normal data since 21/05/2018, when my monthly 3GIG bundle is activated. But 400MB has been deducted. All the data that I have used before 06H00 has not been deducted from the night express. But as soon as the normal bundle is depleted, the night express works correctly. This has been going on for a year now. MTN can't sort it out.
How do I cancel my contract without paying a penalty?