WORST PHONE PROVIDER EVER!

HE WORST PHONE COMPANY EVER.
My 66 year old nan opened a contract out 4 years ago and paid a fee to cancel the contract 2 months or so early only to find out last month they have been taking odd sums of money from her every couple of months for the past 2 1/2 years to the total of £425.53. When calling the company she had to wait 24hrs to speak to a manager which then assured her that an error had happened on the system and she would be refunded the full amount. 5 days later only £175. 50 had been refunded so we contacted the company again only to be told we could not talk to a manager and the lady purposely hung up on us as she "had other people to talk to". I rang straight back and explained what had happened and voila I was put through to a manager straight away. The manager apologised for the situation straight away and said she would refund the full amount owed immediately! We were very pleased. Except we were called back an hour or so later by a very rude member of the "investigations team" to be told the refund had been stopped as we apparently didn't cancel the contract (even though multiple members of the team had told us otherwise...). They then proceeded to make up the lie that we had rang them a month or so after and had apparently reactivated a new simply card but would refuse to tell me the number which we had apparently called of to request this as they said they didn't have it on system (lies). Overall the WORST company with the most disgusting customer service we have ever come across. I would not recommend anybody choose this mobile network unless you would like to be tricked out of money!