The 599 Unli All Net Text is a BOOSTER in BEST EVER MY SUPERPLAN. It is charged ON TOP of the plan. When you added it on your Plan 1799 + 599 makes the total Monthly Recurring Fee of 2398. The 599 was not deducted from your Peso Value. This increase which maybe your credit limit cannot accommodate or is higher than your credit limit so that explains why it is asking for financial proof - so it can increase your credit limit.
For request for credit limit increase, provide any proof of financial capability and email it to email@example.com. Make sure that the attachment/s won't exceed 5MB as it won't be accepted by globe's system.