1.A compromise will be, you pay for HP900UL for the month of April 2007.BSNL can claim, that you asked for change from 1st April. Because of Admn/technical difficulties the metering could not be effected on 1st April.2.BSNL may/can not charge (like Airtel) on prorata basis. It is either Home900Ul or Home250. for full month.3. Suppose you surrender your telephone say, on 10th april . Still they will charge Rental for full month. 4. Consumer Court can also comment on your action,that you were taking advantage to use the system to your benefit, when your INTENTION was clearly to use the service as applicable to Home 250. w.e.f from 1st April. ( in which unlimited download is not allowed).5. I "did not Know" that I should not have used UL facility after applying for change is not proper legal defense. 6. Assume the plan was changed on 20th april. You did not download between 7th and 20th april ( unlimited). Now can you claim you are entitled to download another 18GB, which is your usual download ? ( say 9 GB per week )Conclusion 1.Your INTENTION to Change to Home 250 wef from 1st april will be taken as final, and you may have to shell out the full amount.2. Think of the reverse action. Change from Home 250 to HP900UL. You could have started download (NU) immediately, without waiting for information from BSNL as actual date of change is immaterial in this case. Discuss with your Legal counsel. .