Google generated different metadecriptions than the ones I suggested

If I'm understanding you correctly, your problem is that Google is showing a different Meta Description to the one which you've given, right?

If so, that's perfectly normal. Meta Descriptions are often ignored and replaced with content from within your webpage. If Google doesn't think your description is good based on the users question/query, they will do this.

If I'm understanding you correctly, your problem is that Google is showing a different Meta Description to the one which you've given, right?

If so, that's perfectly normal. Meta Descriptions are often ignored and replaced with content from within your webpage. If Google doesn't think your description is good based on the users question/query, they will do this.

Yep, as Matt said this is very common.

A consideration though is why. Its OK if Google thinks there is a better description for your site if it thinks your doesn't match the site but .... what you then lose is control of the CTR - click through rate. Since CTR is an indirect factor in ranking (a poor CTR will cause your site to rank lower) this is something you may want to address.

Is your meta description relevant? Does it contain text that isn't anywhere on the page it is describing? Does the description match the search intent? Is the SERP it is returning the page for relevant? This may indicate you need a new page and new content to better serve that SERP.