Paying for no wifi

I've been a loyal customer for Lord knows how long. Im at witts end. I've had a Mifi contract with you in the past, not great as my data will stop working during the day for not reason. I've just renewed my mifi contract (1st month) for the 40GB day - 40 GB night data...thinking my data issues would be solved. Well by the 13th it stopped working and by the 15th of this month I had to purchase data. In total for this month, I've bought five times data (go ahead and check) as my wifi during the day has stopped. At 12am it will kick in, I know because I work after hours... which means the router is in working order. I dont download or abuse the internet so not sure where my data is. I've tried to check online what my data situation is, but when propmted to add the 20 digi number, I was told it is incorrect. I have had 2 other persons verify that the number is correctly filled in..Now I have been blocked for 24 hours until trying again...Hope you can understand my frustration. But right now I want to cancel this contract as I'm paying practically double for something I'm not getting. 20 digi number - ‪***‬ Thanks Miss N Reid, Port Elizabeth