I have a website using the Maya Theme hosted on 123 reg. They needed to me upgrade to php 7.
Switching the PHP version to 7.0 has caused website to crash and display the below error message:

There has been a critical error on your website.

Advised that “this is most likely caused by plugins or the theme as they do not support the newer PHP version. This should be resolved by updating your plugins and themes.”

We have tried everything but nothing resolved the issued.

LayerSlider was removed, and the latest version of Maya theme was installed, on activation this gave error messages and theme did not load properly. In an attempt to solve the problem tried de activating plugins starting with woo commerce, and re activating the older theme, this has now brought the error ( page redirected too many times ) Ive tried all the fixes on help pages, clearing cookies, browser cache but only get the same page ( redirected too many times ), last attempt was to change to the default wordpress theme Twenty Twenty, now the ( page redirected too many times ) comes on attempting to access the wp-admin page, seems to be stuck in a loop now.
Can you help get out of this loop or advise on how to?
I was thinking of deleting all plugins and all themes via ftp leaving only TwentyTwenty but not sure if this will help the redirect error.

Ideally I want my Maya theme website back and all updated, but web developed has hit a wall. Really not sure what to do now. Any advice would e appreciated.

The page I need help with: [log in to see the link]