Online surveys have the potential to reach a larger audience compared to other methods. You can highlight that the use of online platforms allowed for broader geographical coverage and the inclusion of participants who may be difficult to reach through other means.

you should enter the response as questionnaire and fill the response in SPSS tool and generate result according to your survey and research

SPSS is one of the best tool to analyze survey questions which are based on various scale and rate.

Likert scale, nominal scale, binomial scale, ratio scale and etc

Nonresponse may bias results because the subpopulation of respondents may be quite different from the population in general. Substituting new respondents for nonrespondents can just make this worse. In addition, your different sources may also represent different populations. You might compare respondent results for different sources to see if there are big differences there.

For nonresponse, you could weight according to response "propensity," though that may be difficult.

In general, you cannot solve a nonresponse problem by taking other data unless you know there are similar characteristics between the member of the population nonresponding, and the member whose response is substituted, and this is still risky and should not be overused. However, I think such methods as "hot deck" might still be used. But that is not what you are doing.

Best wishes.