All the stats on the WCCL website for 2018 to present are generated from the scorecards on the website. So if there is an error in the stats, go to the player info page of the affected player (by clicking their name on a scorecard) and click "More" on the Match Info section. This lists every match they played in, with their batting and bowling returns from the match.
The most likely issue is that there are matches missing from their list. Identify one such match and go to the scorecard for that match. Check if the player is listed on the scorecard. If they are, then click on their name to go to their stats. You'll probably now find the stats for all their missing matches. Basically the website thinks the player is two different people.
If this is the case, then look at the top of the two stats pages. If both are listed as being at the same club, then an administrator from the club (whoever puts the results onto the website after each match) needs to log in and go to the club members page. From there they can select to update their club members, and merge the two instances of this player into a single record. This then has to be approved by the site admin. Once this is done, the stats will all be merged.
If the two instances are listed as being at different clubs, then contact the league's fixtures and results officer, who will transfer the player across to the correct club so the two records can then be merged as above.
It is also possible that there is an error in a scorecard. If this is the case then the league's fixtures and results officer will need to be contacted to resolve the issue. This is also the case for any other issues.