I am unable to pay subscription through my Debit Card

See this support article:--> Payment methods that you can use with your Apple ID - Apple Support

If you still have problems or if you cannot find the information you were looking for, please contact the iTunes Store Support Team directly, using this link:--> iTunes Store & App Store – Get support for various issues, and choosing: your country, then Apple ID, then iTunes & App Store. If your problem is not among the options shown there, tap/click on the option “the topic is not listed” and describe your issue.

Regards

Giulio