EESA worries. Advice welcome

Hello I have been on ESA in the Support Group for a few years now and recently I received a form number ESA3, to complete to see if I was entitled to Income Based ESA instead of Contribution based ESA.

As I have a husband who works more than 24 hours a week I am not eligible but I returned the form with a cover letter politely thanking them but explaining why I was unable to apply.

I received my usual fortnightly ESA payment on the 27th December and my next payment is due on the 10th January but I noticed upon checking my bank account today, that one week's ESA benefit has been paid into my account on the 3rd January. Being a worrying type of person I am now worried in case they have altered my benefit in some way or even worse, could they have stopped it and made this as a final payment to me? I have not received any letters or calls in this matter. I figured that they would write to me if there was nothing major to communicate to me.I am in the support group for a number of serious medical conditions affecting both physical and mental health so I do get very stressed whenever I hear anything from DWP, or notice any changes. Could this be a one off payment that maybe they found I was entitled to or something to be very concerned over? I would appreciate any advice. I try not to call them directly as I suffer from a social anxiety syndrome and I get heart problems when placed under the stress of having to communicate in person or on the telephone with anyone I don't know.

Also are they every likely to end Contribution based ESA? I only ask because it was something my husband was told may be a potential action some time ago .I do hope not.

Thank you for any advice..