Cell C, worst customer service ever, again.

Received and increased bill for end April in March and was upset about this. Contacted Cell C and was advised that my contract expired. requested for both contracts to be cancelled with immediate effect. Was then informed that I HAVE to give a 30 day notice period to cancel, Was then even more upset as I had to give them notice but they did not advise me of any increases in billing amounts and that my contract expired. Advised that good customer relations and retention means keeping your customers informed of changes or contract expirations. Was then assisted and the normal contract amount was then reinstated. now I once again received an invoice for May in April and once again the amount is the increased amount (3x the amount my contract was for). I find this very disheartening and very upsetting. The reason for cancellation was in relation to no communication re expiration of contract and if I had been advised 30 days prior to my contract expiring this would be what would happen I would have cancelled it then and there and we would not be in this situation. I feel this is bad practice and that Cell C do not want to retain their customers. Will never deal with them again.