Who are the ads for or what products are being offered?
Lock screen: maybe the Alcatel's OS has been updated and is now allowing ads. Or again allowing ads that were previously being blocked. The update may have reset the applicable configuration setting(s) that were blocking ads.
Work your way through the configuration settings. Do not change anything - just search and make some notes. Look for possible settings that can be changed.
Make a list and then go back starting with the most likely candidates that can be enabled or disabled as applicable to stop the ads.
Bear in mind that some blockers do not or cannot block all ads. Some blocking software developers are being paid to allow certain ads anyway.
Despite the device...