BT and O2 do likewise - I have just had notification of mine.
The 10% referred to by the OP is rather high considering CPI was 0.8% in January.
I notice that they do not say CPI + 3.7% which would be 4.5%, whereas the "combined" would be 4.5296% - maybe just a small difference but when taken across the who customer bas would give them a tidy sum.
The OP needs to ask TT to justify their increase against te contract.
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