homealone

I had my bill yesterday, I upgraded via the tier upgrade site on 9th March.

I was billed in arrears for 750Kb from 17th Feb to 9th March & for 2Mb from 10th March to 16th March. No problem.

However I was also billed in advance for 2Mb from 17th March to 16th April.

Does anyone know if this is normal & will be adjusted automatically on the next bill, or should i give them a ring?