Hello @naumanafridi987,
Thank you for your query and we are so sorry about the trouble this must have caused.
It is a pretty common thing with Google these days. It happens with 70% of the results and we even have a KB dedicated to this problem and a few solutions we recommend:
https://rankmath.com/kb/different-meta-title-and-description/
Please check the KB and you will understand the reasons Google does this.
Google has made some changes to their algorithm which automatically changes the titles, discarding the one you have set in your SEO title meta tag. This happens regardless of the SEO plugin you are using. We have covered this Google update here:
https://rankmath.com/google-update/google-title-rewrite-update/
Hope that helps, and please do not hesitate to let us know if you need our assistance with anything else.