walmart family mobile continues to charge for line that were supposed to be cancelled 2 mths ago Nationwide

I called to cancel 2 lines on my plan in June and was told my bill would only be $75. I was billed $145 in june and called several times as well as emailed customer relations to correct the error. The bill was never adjusted and i was made to pay it being told the next bill would be correct. Here it is almpost August and Im still being charged for 4 lines! Customer support and customer relations will do nothing to fix this error! Customer relations will not respond to any emails and does not do anything im told by customer support that they would do.