User Activity

I received an email today saying my tariff has now changed, with a higher data usage. I have not asked for this, are O2 realigning their tariffs or do i need to contact customer service to dispute this?
When I got my contract it was for 30gb with an additional 20gb, I am now outside my 24 month minimum term and can only see 30gb in my data allowance. Does the extra amount disapper after your contract term is up?
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