NO LONGER ABLE TO GENERATE NEURAL VOICES (error 403) after unsuspending my subscription

I have the F0 plan and I m using the text to speech neural voice generation api. I m very far from having exceedeed my quota since i only generate a few short texts per month. I got my FRE trial subscription suspended after 30 days, forcing me to pick a pay as you go plan (but keeping my free credits in the F0 plan). Despite having opted for the pay as u go and kept the F0 plan, I still get a 403 error when trying to generate new voices. when asking for help, the system redirects me to a page where i m being asked to move to the standard plan (not free) to fix the 403 error: BEAUTIFUL NEW UPSELL from Azure (everytime u get in trouble u are asked to pay something or upgrade something). Its supposed to be FREE!

"For the fastest results, we recommend upgrading your tier to (S0) Standard:

Go to your Speech Service resource on Azure Portal.
Select the Pricing Tier Blade.
Select the S0 Standard option.
Call the API / Service again, and you should see the 403 Quota error resolve."

what s up now ? please explain how i can keep on using my F0 plan :

The cost of your Cognitive Services depends on the actual usage and the options you choose below. Learn more
F0 Free
Speech Translation
5 hours per month
Speech-to-text
5 hours per month
Custom Speech-to-text
5 hours per month
Custom Speech model deployment
1 model
Text-to-speech
5M characters per month
Custom Text-to-speech
5M characters per month
Custom Voice Model
1 model
Neural Text-to-speech
Only East US, South East Asia & West Europe. 500K char/month
0.00
USD PER HOUR (ESTIMATED)

thanks