Any “singular/plural” Vs “a”

Question

should I use any with singular or plural nouns in the following context? And can I use a instead?

1. If you have any complaints with respect to any programme(s) on this channel, please inform us.

2. If you have any complaint with respect to any programme(s) on this channel, please inform us. 

3. If you have a complaint with respect to any programme(s) on this channel, please inform us.

Answer 1

You are correct in thinking that

any

can be used with plural and singular, and

a

is used with singular.